A review of the research work of Professor Predrag Marjanović

Chemical Engineering and Processing 44 (2005) 141–151

A review of the research work of Professor Predrag Marjanovic

David Mills∗

Pneumatic Conveying Consultant, Old Wives Lees, Canterbury CT4 8BQ, UK

Received 6 August 2003; received in revised form 18 December 2003Available online 20 June 2004

Abstract

Predrag Marjanovic was born on 1 May, 1951 in Belgrade, Yugoslavia, where he lived until November 1992. He moved with his wifeMara and daughter Nevena to Glasgow, Scotland, where he continued to reside throughout his time in the UK. I was supervisor of his Ph.D.programme and colleague in Glasgow for about 5 years. Predrag’s involvement in research covered a diverse range of topics, includinghydraulic transport, fluid mechanics, bulk material characterisation and hopper design. This review will mostly feature the work undertakenfor his Ph.D. and that associated with pneumatic conveying. A definitive list of Predrag’s references, however, is appended. Predrag diedsuddenly on 14 September, 2001.© 2004 Elsevier B.V. All rights reserved.

Keywords: Fluid mechanics; Hopper design; Vertical pipeline; Pneumatic conveying; Inclined pipeline; Pipeline bends; Rubber hose; Dense phase

1. Belgrade

Predrag obtained a 1st class Honours degree in Mechan-ical Engineering in 1975 from the University of Belgrade.He then joined the Fluid Mechanics Department of the Uni-versity of Belgrade as a teaching assistant, where he wasemployed for 18 years, rising to the position of AssociateProfessor. During this time he obtained an M.Sc. with dis-tinction in Process Engineering. His M.Sc. was on the Ex-perimental Determination of Gas–Solids Friction Factors. Inthese early years, he also published a number of papers onhydraulic conveying with Professor M. Sasic.

I met Predrag in Belgrade in October 1979, being in-troduced by Dr. Z. Bukerov from the University of NoviSad. Predrag expressed the desire to undertake a Ph.D. pro-gramme on pneumatic conveying and particularly wantedto investigate conveying vertically up in dense phase. Therewas the opportunity of undertaking such a programme ofresearch at Thames Polytechnic (now the University ofGreenwich) in London, where I was a Senior Lecturer inthe Department of Mechanical Engineering, and ProfessorStan Mason was Head of Department. Predrag obtainedsabbatical leave from the University of Belgrade and cameto London early in 1982.

∗ Tel.: +44 1227 732493; fax:+44 1227 732504.E-mail address: [email protected] (D. Mills).

2. Ph.D. programnme

A high-pressure (7 bar gauge) top discharge blow tankhaving a 1 m3 capacity was made available and a pipelinewas built on the outside wall of the building, which alloweda 17 m vertical rise. With a need to re-circulate materials fortest purposes it was necessary to run the pipeline both upand down the wall to complete the circuit. It was decided,therefore, to investigate pneumatic conveying performancein both the vertically up and vertically down sections of thepipeline as it involved little additional effort in building andinstrumenting the test facility for the added data. There wasalso a lot of interest at the time in the pneumatic conveyingof various materials down vertical mine shafts. A sketch ofthe test pipeline facility is provided inFig. 1.

Two pipelines, in fact, were built, one of 2 in. nominal(53 mm actual) bore and another of 3 in. nominal (81 mm ac-tual) bore. This was to allow the influence of pipeline bore tobe additionally investigated. The two pipelines ran alongsideone another and so the pipeline routing and geometry wasalmost identical for the two pipelines. The pipelines werebuilt on the rear wall of the building and this had a fire escapeaccess with a large platform. As a consequence, because ofthe convenience, it was decided to install sight glasses in thetwo pipelines in both the vertically up and vertically downsections. I had full video facilities available from the UKDepartment of Trade and Industry for the research work.

0255-2701/$ – see front matter © 2004 Elsevier B.V. All rights reserved.doi:10.1016/j.cep.2004.05.002

142 D. Mills / Chemical Engineering and Processing 44 (2005) 141–151

Fig. 1. Test facility and pipeline employed.

In order to derive data for the individual sections ofpipeline in isolation from the total pipeline, all four sectionsof vertical pipeline were provided with pressure tappingsalong their entire length. In the vertically down sections ofpipeline, there were seven sets of pressure tappings and inthe vertically up sections, there were eight sets. A ring offour pressure tappings was provided at every location andthese were inter-connected. Every pressure tapping was fit-ted with a filter pad and provided with a high-pressure airpurging facility, which was routinely operated after eachand every test run. Bearing in mind that this was 1982 andthat electronic pressure transducers were both in their in-fancy and very expensive, mercury manometers were usedfor all vertical pipeline pressure measurements.

Two typical sets of pressure measurement data for thevertically down and vertically up sections of pipeline arepresented inFig. 2. This shows the location of the pressuretappings and their proximity to the various bends in thepipeline. The data relate to the pneumatic conveying of a finegrade of pulverised fuel ash. Five different bulk particulatematerials were investigated in the research programme, theother four being barytes, bentonite, cement and fluorspar.All five materials were capable of being conveyed in densephase and hence at low velocity.

Typical conveying data obtained for the total pipeline sys-tems are presented inFigs. 3–6.

Several compressors, each capable of delivering 200 ft3/min (0.095 m3/s) of free air at a pressure of 100 psig (7 bargauge) were available, together with a desiccant-type airdrier. For the 53 mm bore pipeline, one compressor wasused and for the 81 mm bore pipeline two were used.Convergent–divergent choke flow nozzles were used to mea-sure and control the flow rate of air used for conveying, aswell as to control the discharge rate of material from the blowtank. The receiving hopper was mounted on load cells andthese were used to measure the conveyed material flow rate.

Fig. 2. Pressure gradient results for a fine grade of pulverised fuel ash.

The discharge limit of the blow tank used was about26 tonne/h with the 53 mm bore pipeline and approximately50 tonne/h with the 81 mm bore pipeline. Within this capa-bility of the conveying facility, however, tests were carriedout with conveying line pressure drop values of well overtwo bar and the materials were all capable of being con-veyed at solids loading ratios of well over one hundred. Aminimum of fifty individual tests were undertaken with ev-ery material/pipeline bore combination, in order to draw thevarious families of curves required.

There was no lower limit on pressure drop, material flowrate or solids loading ratio that the test facility could operate,

Fig. 3. Conveying characteristics for bentonite in 53 mm bore pipeline.

D. Mills / Chemical Engineering and Processing 44 (2005) 141–151 143

Fig. 4. Conveying characteristics for fluorspar in 53 mm bore pipeline.

but Predrag chose to investigate dense phase conveying forhis Ph.D. study and he just did not have the time availableto extend the work down into the dilute phase range of con-veying. As a consequence very few tests were undertakenwith a conveying line pressure drop below 0·8 bar.

3. Pressure gradient data

Data was recorded from the manometer banks from eachtest and this was analysed in terms of a pressure gradientin mbar/m. The resulting data was also plotted in the formof conveying characteristics, and representative sets of dataobtained are presented inFigs. 7–10. In Figs. 7 and 8, dataobtained for vertically upward flow are shown, with cementin the 53 mm bore pipeline inFig. 7and barytes in the 81 mm

Fig. 5. Conveying characteristics for cement in 81 mm bore pipeline.

Fig. 6. Conveying characteristics for pulverised fuel ash in 81 mm borepipeline.

bore pipeline inFig. 8. As will be seen, almost the entiredense phase conveying capability of the materials has beencovered in the programme of work.

Conveying data presented in this form clearly showthe capability of pneumatic conveying systems and theinter-relating effects of pressure, material concentrationand pipeline bore, as well as air flow rate when designinga system to convey a material at a given flow rate, over aspecified distance. Since there is generally a limit on airsupply pressure, a compromise has to be made betweensolids loading ratio and pipeline bore.

Figs. 9 and 10show data obtained for vertically downwardflow in the 53 mm bore pipeline, with cement inFig. 9 andbarytes inFig. 10. From these two sets of data, it will be

Fig. 7. Pressure gradient for cement in 53 mm bore vertically up pipeline.


Fig. 8. Pressure gradient for barytes in 81 mm bore vertically up pipeline.

seen that when the materials are conveyed at a solids loadingratio of about 35, there is no pressure drop associated withthe conveying of the materials. Results with the other threematerials also showed the same pattern. At higher solidsloading ratios, the pressure gradient is negative and hencethere is a pressure recovery in downward flow. At lowervalues of solids loading ratio, however, the pressure gradientis positive, and hence by inference over the entire dilutephase range of conveying, there will be a pressure drop.

4. Subsequent collaboration

Following Predrag’s return to the University of Belgrade,and the award of his Ph.D. in 1984, Predrag maintained

Fig. 9. Pressure gradient for barytes in 53 mm bore vertically downpipeline.

Fig. 10. Pressure gradient for pulverised fuel ash in 81 mm bore verticallydown pipeline.

his collaboration with myself and published numerous pa-pers on the many aspects of his Ph.D. research programme,including dense phase conveying, pipeline bore, materialinfluences and blow tank performance. The collaborationwas continued with Predrag being involved in my contin-uing research work, and this included papers on pipelineorientation, pipeline material and the influence of bends inpneumatic conveying pipelines. The nature of the work andthe range of topics will be seen from the list of date orderedreferences and publications at the end of this paper.

5. Scaling parameters

With my work on horizontal conveying, and Predrag’swork on vertical conveying, using many of the same materi-als, it was a natural development of our joint work to com-pare data and derive scaling parameters for vertical pipelinesin terms of horizontal pipelines. InFig. 11, data are pre-sented on pressure gradients for the conveying of barytes ina horizontal pipeline of 53 mm bore. Predrag had obtainedidentical data for conveying vertically up and so to providea comparison of the two sets of results a rectangular gridwas placed on both sets of curves and the value of the ra-tio of the two pressure gradients was noted.Fig. 12showsthe value of the ratios of the vertical line pressure gradientdivided by the horizontal line pressure gradient, determinedfor every grid point.

It will be seen that the relationship obtained covers a verywide range of conveying conditions, although it is unfortu-nate, in this case, that the data could not be extended to coverdilute phase conveying also. This exercise was also carriedout with a number of other materials and very similar resultswere obtained. In all cases, the ratio between vertical andhorizontal pressure gradients was in a very narrow band, at


Fig. 11. Pressure gradient for barytes in 53 mm bore horizontal pipeline.

Fig. 12. Ratio of vertical to horizontal pressure gradient for barytes in53 mm bore pipeline.

a mean value of about 2, over the entire range of conveyingconditions considered.

6. Pipeline bends

In my work for the Department of Trade and Industry inthe UK, I had generated a considerable amount of data witha number of different materials conveyed through pipelinesof approximately 100 m in length but having differing num-ber of bends. Predrag worked with me to analyse the dataand isolate the influence of the straight pipeline so that theeffects of the bends could be determined. Recognising thatengineers design pneumatic conveying systems in differentways, the data were analysed in order to provide values bothin terms of an equivalent length and in terms of an actualpressure drop value.

Fig. 13. Equivalent length of bends.

Data obtained with cement and analysed in terms of anequivalent length of straight horizontal pipeline are pre-sented inFig. 13. This is for 90◦ bends having a bend diam-eterD, to pipe bored, ratio of 24:1 in 53 mm bore pipelinein horizontal plane. Almost identical results were obtainedwhen a similar analysis was carried out for the conveying ofbarytes. A simple correlation in terms of the conveying lineinlet air velocity was not expected, but it was not possibleto determine any effect of the position of the bends in thepipeline. Data obtained with barytes and analysed in termsof a pressure drop across a bend are presented inFig. 14.Once again, almost identical results were obtained for theconveying of cement. These data are for the same bends re-ported inFig. 13.

Fig. 14. Pressure loss for bends.


7. Pipeline material

Another area of interest at this time was the transport ofcement and drilling mud powders, with a particular require-ment for the transferring of these materials onto off-shoredrilling platforms. This involves the use of flexible hose fora significant proportion of the pneumatic conveying pipelinefor the transport of these materials. There was, therefore, aneed to know how pressure drop through rubber hose com-pared with the pressure drop through steel pipeline. Oil wellcement and barytes were the materials used for this partic-ular investigation. 40 m of rubber hose of 53 mm bore wasavailable and so a 40 m long pipeline was built of 53 mmbore steel pipeline and a full set of conveying characteris-tics were obtained for each material. The rubber hose wasthen strapped to the steel pipeline to create a pipeline hav-ing exactly the same routing and number of bends and bendgeometries. Full sets of conveying characteristics were thenobtained for the two materials conveyed through this rubberhose pipeline.

The conveying characteristics for the oil well cement con-veyed through the steel pipeline are presented inFig. 15.Once again as wide a range of conveying conditions wereinvestigated as possible. Similar sets of conveying character-istics were obtained for the barytes in the steel pipeline andfor both materials in the rubber hose pipeline. The rubberhose was rated to a 10 bar capability.

A rectangular grid was constructed on each set of convey-ing characteristics, as in the above analysis, and the ratio ofpressure drops was evaluated at corresponding grid pointsof material and air flow rates. InFig. 16, a comparison ofthe pressure drop required to convey the cement throughthe rubber hose, compared with that to convey the cementthrough the steel pipeline, is presented. It will be seen that

Fig. 15. Conveying characteristics for cement in 40 m long steel pipeline.

Fig. 16. Comparison of pressure drop data for steel and rubber hose linesfor cement.

the percentage differences between the two pipeline mate-rials follow a regular pattern. With increase in air flow ratethere is a significant increase in the pressure drop requiredfor the rubber hose line. The lines drawn through the dataalso approximate to lines of mean value of conveying airvelocity through the pipeline.

It is believed that this can be related to the differences incoefficient of restitution between the conveyed particles andthe pipeline walls. On impact with the rubber, the particleswill be decelerated, since the rubber will absorb much ofthe energy of impact. As a consequence, the particles willhave to be re-accelerated back to their terminal velocity. Thecoefficient of restitution of the particles against the steelpipeline wall will be very much lower. This effect is clearlymagnified by increase in velocity and explains why there islittle difference between the two pipeline materials in lowvelocity dense phase conveying, but differ by 50% in highvelocity dilute phase conveying. The results obtained withthe barite were very similar.

8. Glasgow

In 1988, I and a number of colleagues moved to GlasgowCollege (now Glasgow Caledonian University) to join Pro-fessor Stan Mason who had moved there the previous yearand was later appointed Principal and Vice Chancellor ofthe University. A major teaching aim was to provide a post-graduate Masters Degree course in Bulk Solids Handlingin Glasgow. To help in the preparation and development ofthis new and innovative venture, and early teaching on thecourse, Pregrad obtained sabbatical leave for a year from theUniversity of Belgrade in 1990/91.


Predrag joined Glasgow Caledonian University in 1992as Senior Research Fellow and was appointed Professor in1999. In Glasgow, Predrag’s research work expanded con-siderably, with the supervision of Ph.D. programmes, con-tract research and in the undertaking of consultancy work.In 1998, for instance, his CV lists 13 publications. Hiswork in this period included major programmes on inclinedpipelines, bend losses, very high-pressure conveying sys-tems, hopper design, on-site measurements, and materialdegradation and segregation. I have concentrated on the firstthree of these topics as they represent the largest proportionof Predrag’s published output.

9. Inclined pipelines

The performance of inclined pipelines has long been atopic of mystery and contention and so Predrag set up anexperimental facility in the laboratory at Glasgow Caledo-nian University in order to study the problem. A 100 m longpipeline of 81 mm bore was built, having a section in thecentral area which was 8 m long and that could convenientlybe adjusted to provide inclinations ranging from−20◦ to+90◦. Material was fed by means of a rotary valve, and aRoots-type blower capable of delivering up to 0·33 m3/s offree air was used, giving superficial air velocities from 10to 20 m/s. A series of seven papers over a period from 1994to 1997 were written specifically on this subject, with var-ious distinguished co-authors, as will be seen from the listof publications.

A major feature of the work was the analytical modellingof the inclined pipeline situation using computational fluiddynamics, and comparing the numerical predictions with theexperimental results. Test results obtained with 3 mm poly-mer pellets are presented inFigs. 17 and 18. In Fig. 17, theresults are presented in terms of the difference between the

Fig. 17. Variation of pressure gradient difference with angle of inclination.

Fig. 18. Variation of normalised pressure gradient with angle of inclination.

total pressure gradient for an inclined pipe and that for ahorizontal pipe, under the same flow conditions, as a func-tion of the angle of inclination. Data are presented for solidsloading ratios of 5, 10 and 20. It should be noted that thepressure gradient for horizontal flow is also dependent uponthe solids loading ratio and, in addition, increases continu-ously as the solids loading ratio increases.

In Fig. 18, the results are presented in terms of a nor-malised pressure gradient, which is the ratio of the pressuregradient for a particular angle of inclination divided by thatfor the horizontal. Once again, solids loading ratios of 5, 10and 20 were considered.

10. Pipeline bends

Pipeline bends are another area of particular interestto pneumatic conveying engineers on which Predrag hasworked. A series of six papers over a period from 1995to 2000 were written specifically on this subject, workingmostly with the same group of co-authors as above. Forthe majority of the work, very little new experimental workwas undertaken, for once again the main thrust of the workwas on modelling, and for this purpose two sets of existingdata were used.

One of the sets of data used was that for cement, obtainedby the author in a 50 m long pipeline of 53 mm bore thatcontained 99◦ bends having aD/d ratio of 24:1. The otherset of data was for polyethylene pellets conveyed through a50 m long pipeline of 80 mm bore that contained six ninetydegree bends having aD/d ratio of 8·5:1 and obtained laterfrom the laboratory in Glasgow. The modelling employed asolids friction coefficient and the authors attempted to modelthe experimental data.

The model was capable of separating the constituent ele-ments of the total pipeline pressure drop and so the authors


Fig. 19. Cement in 53 mm bore pipeline with nine bends.

Fig. 20. Polyethylene in 80 mm bore pipeline with six bends.

were able to demonstrate the proportion of the total pres-sure drop that could be attributed to the bends. The resultsfor the cement are presented inFig. 19 and those for thepolyethylene pellets inFig. 20. Both materials were capableof being conveyed in dilute as well as dense phase, althoughat low velocity, the cement was conveyed in a sliding bedmode of flow and the pellets in plug flow. Influence of bendson pressure drop required to convey materials in 50 m longpipelines is shown inFigs. 19 and 20.

11. High-pressure conveying

Very high-pressure conveying is a subject of particular in-terest of mine, and this was another topic on which Predragworked. A series of five papers over a period from 1995 to1997 were written specifically on this subject. The test fa-cility used was designed and built in the laboratory at Glas-gow Caledonian University under my supervision, with testwork carried out in which material was conveyed from the

Fig. 21. High-pressure conveying facility and pipeline.

high-pressure blow tank and into a reception vessel main-tained at pressures of up to 20 bar gauge. The blow tankfeeding the conveying system was rated at 25 bar and thesystem was tested to 32 bar. The filter unit was located in-side the pressurised reception vessel.

In the work undertaken by Predrag, crushed coal wasconveyed, and so nitrogen was used as the conveying gas.Modelling of system performance was a major part of theprogramme once again. The conveying pipeline employedwas 78 m long, of 49 mm bore and included eight 90◦ bends.A sketch of the test facility and pipeline is given inFig. 21.A number of sets of test results obtained for different backpressures and line pressure drops are presented inFig. 22.

Minimum conveying air velocity was also determined dur-ing the test programme. It was found that this velocity is in-fluenced by system pressure, with its value decreasing from10.5 m/s at atmospheric pressure to 6 m/s at a pressure of20 bar gauge. This effect was expected due to a significantincrease of gas density at higher pressures.

Fig. 22. Conveying characteristics for coal at different back pressures.


12. What could have come

We are naturally left wondering what might have beenachieved with so many more years that should have been his,to spend on the loves of his life: his family and his researchwork, and not forgetting the golf that he discovered in hisnew home in Scotland. Thank you for being such a valuedcolleague and friend. You will be long remembered by usall.

Further reading

References and publications

[1] P. Marjanovic, M. Sasic, Hydraulic transport of ash in thermo-power stations, Proceedings of the 4th Yugoslav Thermal Symposium,Belgrade, Yugoslavia, 1975 (in Serbian).

[2] M. Sasic, P. Marjanovic, On the methods for calculation of hydraulictransport and their reliability in practice. Part 1, Proceedings of the5th International Conference on Hydraulic Transport of Solids inPipes, vol. 1, Hanover, Germany, 1978, pp. A5:61–A5:76.

[3] M. Sasic, P. Marjanovic, On the methods for calculation of hy-draulic transport and their reliability in practice. Part 2, 5th Interna-tional Conference on Hydraulic Transport of Solids in Pipes, vol. 2,Hanover, Germany, 1978, pp. X2–X3.

[4] P. Marjanovic, Experimental determination of gas–solids friction fac-tor, M.Phil. Thesis, University of Belgrade, Yugoslavia, 1978 (inSerbian).

[5] M. Sasic, P. Marjanovic, Hydromechanics of gas–solid systems, JnlTehnika-Masinstvo, no. 6, Belgrade, Yugoslavia, 1979, pp. 1–9 (inSerbian).

[6] P. Marjanovic, J. Jovanovic, R. Askovic, Sur l’ecoulement d’unliquide conducteur dans la region d’entree un tube circulaire enpresence d’un champ magnetique. Publ. of Mathematical InstituteSANU, new series, vol. 3, no. 11, Belgrade, Yugoslavia, pp. 75–80.

[7] M. Sasic, P. Marjanovic. One more general approach for investigationof hydro-mechanics of two-component systems, J. Powder BulkSolids Tech. 5 (1) (1981) 13–19.

[8] M. Sasic, P. Marjanovic, Non-isothermal compressible flow in pipes,ZAMM 62 (1982) 226–228.

[9] P. Marjanovic, A comparative study of performance characteristics forhorizontal and vertical pneumatic conveying in pipelines, Proceedingsof the Pneumatech 1. PAC Conference Stratford-upon-Avon, UK,1982.

[10] D. Mills, J.S. Mason, P. Marjanovic, Pneumatic conveying – verticallydown. Proceedings of the 8th Powder and Bulk Solids Conference,Atlanta, USA, May 1983, pp. 546–557.

[11] D. Mills, J.S. Mason, P. Marjanovic, An analysis of the dense phasepneumatic conveying of cement in vertical pipelines. Proceedings ofthe 9th Powder and Bulk Solids Conference, Chicago, USA, May1984, pp. 125–147.

[12] D. Mills, J.S. Mason, P. Marjanovic, The influence of pipelinebore on dense phase pneumatic conveying in vertical pipelines.Proceedings of the 16th Yugoslav Congress on Theoretical andApplied Mechanics, Becici, Yugoslavia, May/June 1984, pp. 261–269.

[13] P. Marjanovic, An investigation of the behaviour of gas–solids mix-ture flow properties for vertical conveying in pipelines, Ph.D. Thesis,CNAA, Thames Polytechnic, London, UK, 1984.

[14] D. Mills, J.S. Mason, P. Marjanovic, The influence of product typeon dense phase pneumatic conveying in vertical pipelines, Proceed-ings of the Pneumatech 2, Powder Advisory Centre Conference,Canterbury, UK, September 1984, pp. 193–210.

[15] D. Mills, J.S. Mason, P. Marjanovic, A comparison of pressure dropsin horizontal and vertical dense phase pneumatic conveying, Proceed-ings of the 3rd International Conference on Pneumatic Conveying,Pecs, Hungary, March 1985.

[16] D. Mills, P. Marjanovic, J.S. Mason, An analysis of line pressuregradient for dense phase vertical gas–solids flow, Proceedings of theGAMM Congress, Dubrovnik, Yugoslavia, April 1985.

[17] P. Marjanovic, D. Mills, J.S. Mason, An investigation of high con-centration vertical pneumatic conveying, J. Procesna Tehnika, vol. 1,no. 2, Belgrade, Yugoslavia, December 1985, pp. 39–49 (in Serbian).

[18] P. Marjanovic, On the choking velocity for vertical pneumatic con-veying, Proceedings of the 17th Yugoslav Congress of Theoreticaland Applied Mechanics, Zadar, Yugoslavia, 1986 (in Serbian).

[19] P. Marjanovic, The design of vertical pneumatic conveying usinghigh-pressure blow tank system, Proceedings of the InternationalColloquium on Modern Trends in the Development of PneumaticConveying, Sarajevo, Yugoslavia, June 1986, pp. 45–64.

[20] P. Marjanovic, D. Mills, J.S. Mason, A method of calculatingflow parameters for pneumatic conveying in pipelines, Proceedingsof the Pneumatech 3, PAC Conference, Jersey, UK, March 1987,pp. 143–167.

[21] P. Marjanovic, I. Vuskovic, L. Bodiroga, Hydraulic Transport ofgranular activated carbon in water refinery plant, Symposium onWater Supply, Belgrade, Yugoslavia, 1987 (in Serbian).

[22] P. Marjanovic. Bends in gas–solids mixture flow in pipes – a view tothe prediction of pressure loss, GAMM Congress, Vienna, Austria,1988.

[23] P. Marjanovic, Analysis of the change of flow parameters in dis-continuous pneumatic conveying systems, Proceedings of the 18thYugoslav Congress of Theoretical and Applied Mechanics, VrnjackaBanja, Yugoslavia, 1988, pp. 89–92 (in Serbian).

[24] P. Marjanovic, Determination of performance characteristics of dilutephase pneumatic conveying system, Proceedings of the 3rd Sympo-sium of Process Industry Applications, Belgrade, Yugoslavia, 1988,pp. 215–223 (in Serbian).

[25] P. Marjanovic, A comparison between pneumatic and hydraulic con-veying, Proceedings of the 19th Yugoslav Congress of Theoreticaland Applied Mechanics, Ohrid, Yugoslavia, 1990, pp. 61–66 (in Ser-bian).

[26] P. Marjanovic, D. Mills, J.S. Mason, The influence of bends on theperformance of a pneumatic conveying system, Proceedings of the15th Powder and Bulk Solids Conference, Chicago, USA, June 1990,pp. 391–399.

[27] P. Marjanovic, D. Mills, J.S. Mason, The influence of pipeline ma-terial on the performance of pneumatic conveying systems, Proceed-ings of the Pneumatech 4, Glasgow, UK, June 1990, pp. 453–464.

[28] N. Barbalic, P. Marjanovic, E. Dzaferovic, Z. Mujcinovic, A. Cam-para, Measurement of P.F. ash pneumatic conveying system parame-ters in thermo-power station ‘Ugljevik-1’, J. Procesna Tehnika, vol.7, no. 1, Belgrade, Yugoslavia, 1991, pp. 23–26 (in Serbian).

[29] P. Marjanovic, M. Stanojevic, B. Todorovic, A. Vlajcic, The influ-ence of variable operating conditions on the design and exploitationof air-slide systems in thermo-power stations, Proceedings of theRelPowFlo 2, EFChE Publication Series no. 96, Oslo, Norway, 1993,pp. 659–671.

[30] P. Marjanovic, Modelling the transient behaviour of blow tank pneu-matic conveying system. Powder handling and processing, Trans.Tech. Pub. 5 (3) (1993) 219–226.

[31] P. Marjanovic, Pneumatic conveying in an inclined pipeline: inappro-priate, unfortunate or wrong concept? Proceedings of the 19th Powder& Bulk Solids Conference, Chicago, USA, May 1994, pp. 235–251.

[32] P. Marjanovic, D.J. Mason, Gas–solid flows in an inclined pipeline,Proceedings of the 1st International Particle Technology Forum, vol.3, Denver, USA, August 1994, pp. 466–471.

[33] P. Marjanovic, Assessing the flow properties of powdered materials,IMechE Seminar on Hoppers and Silos, London, UK, 1994.


[34] P. Marjanovic, V. Djordjevic, On the compressible flow losses throughabrupt enlargements and contractions, J. Fluids Eng. Trans ASME116 (1994) 756–762.

[35] P. Marjanovic, D. Geldart, J.L.R. Orband, T. Mooney, A comparativeanalysis of two hopper design methods, Proceedings of the Interna-tional Congress for Particle Technology – PARTEC 95, Nürnberg,Germany, March 1995, pp. 69–78.

[36] B. Armstrong, M.G. Jones, P. Marjanovic, G. Welford, P.J. Blenkin,R.G. Holder, An evaluation of the effects of high system pressureon the performance of pneumatic coal conveyors, Proceedings of the20th International Conference on Coal Utilization & Fuel Systems,Clearwater, USA, 1995, pp. 393–403.

[37] T. Mooney, P. Marjanovic, Bend pressure loss in a pneumatic con-veying system, Proceedings of the 20th Powder & Bulk Solids Con-ference, Chicago, USA, May 1995, pp. 61–73.

[38] P. Marjanovic, G. Welford, M.G. Jones, Pneumatic conveying of coalagainst high back pressures, Proceedings of the 12th InternationalPittsburgh Coal Conference, Pittsburgh, USA, September 1995.

[39] M.G. Jones, P. Marjanovic, G. Welford, The prediction of pneumaticconveying performance when conveying into back pressures up to20 bar, Proceedings of the 1st International Conference BULK ASIA,Singapore, 1995, pp. 107–115.

[40] R.J. Hitt, P. Marjanovic, A computer technique to develop a modelof vertical dense phase gas–solids flow from experimental data.Proceedings of the 1st International Symposium on Two-Phase FlowModelling and Experimentation, vol. 1, Rome Italy, October 1995,pp. 67–74.

[41] P. Marjanovic, M.G. Jones, Assessment of a new technique formeasuring flow properties of powdered materials stored in hoppers,IMechE J. Process. Mech. Eng. 210 (1996) 1–8.

[42] P. Marjanovic, Theoretical and practical silo design, Seminar onStorage and Transportation of Bulk Solids, Moreton-in-Marsh, UK,March 1996.

[43] M.G. Jones, P. Marjanovic, Maintaining product quality in pneumaticconveying, Proceedings of the Conveyorex 96 Seminar, Harrogate,UK, April 1996.

[44] P. Marjanovic, G. Welford, M.G. Jones, Pneumatic conveying ofsolids at high system pressures, Proceedings of the 21st Powder &Bulk Solids Conference, Chicago, USA, May 1996, pp. 91–98.

[45] M.G. Jones, P. Marjanovic, The modification of material propertiesfor improved flow characteristics, Proceedings of the Seminar onSolving Problems in Hopper and Silo Systems, IMechE, London,UK, June 1996.

[46] P. Marjanovic, D.J. Mason, T. Mooney, The Performance of a pneu-matic conveying system which incorporates an inclined pipeline sec-tion, Proceedings of the 1st International Conference on Pneumaticand Hydraulic Conveying Systems, Florida, USA, 1996.

[47] D.J. Mason, P. Marjanovic, A. Levy, A simulation system for pneu-matic conveying systems, Proceedings of the 1st International Con-ference on Pneumatic and Hydraulic Conveying Systems, UEF Con-ference, Florida, USA, 1996.

[48] P. Marjanovic, D.J. Mason, The transient flow conditions duringfeeding pneumatic conveying system using high-pressure blow tank,Proceedings of the 12th International Congress of Chemical andProcess Engineering. Prague, Czech Republic, August 1996.

[49] D.J. Mason, A. Levy, P. Marjanovic, Modelling the influence of bendson the flow of gas-solids mixture through pipelines, Proceedings ofthe 12th International Congress of Chemical and Process Engineering,Prague, Czech Republic, August 1996.

[50] A. Levy, P. Marjanovic, D.J. Mason, A Comparison of analyticaland numerical models for gas-solid flow through straight pipe ofdifferent inclinations with experimental data, Proceedings of the 12thInternational Congress of Chemical and Process Engineering, Prague,Czech Republic, August 1996.

[51] P. Marjanovic, Determination of bulk solids indices using the Johan-son indicizer system, Proceedings of the Bulk 96 Design Seminar,Manchester, UK, December 1996, pp. 233–238.

[52] T. Mooney, A. Levy, P. Marjanovic, D.J. Mason, An investigationof gas–solids flow through inclined pipes, Proceedings of the 1997Jubilee Research Event, vol. 1, Nottingham, UK, 1997, pp. 425–428.

[53] P. Marjanovic, M.G. Jones, G. Welford, Pneumatic conveying ofsolids at high system pressures, J. Powder/Bulk Solids Technol. 1 (1)(1997) 3–7.

[54] P. Marjanovic, M. McGarvey, R.B. McKay, Development of lab-oratory methodology to determine flow properties of organic pig-ment powders, Proceedings of the 2nd Israel Conference for Con-veying and Handling of Particulate Solids, Jerusalem, Israel, 1997,pp. 2.28–2.33.

[55] A. Levy, T. Mooney, P. Marjanovic, D.J. Mason, Analytical, Nu-merical and experimental investigations for gas–solid flow throughstraight pipe of different inclinations, Proceedings of the 2nd Is-rael Conference for Conveying and Handling of Particulate Solids,Jerusalem, Israel, 1997, pp. 4.30–4.35.

[56] D.J. Mason, A. Levy, P. Marjanovic, The influence of bends on theflow of gas-solids mixtures through pipelines, Proceedings of the2nd Israel Conference for Conveying and Handling of ParticulateSolids, Jerusalem, Israel, 1997, pp. 4.36–4.41.

[57] P. Marjanovic, D.J. Mason, Gas solids flow in an inclined pipeline.Powder handling and processing, Trans. Tech. Pub. 9 (3) (1997)217–220.

[58] A. Levy, T. Mooney, P. Marjanovic, D.J. Mason, A comparison ofanalytical and numerical models with experimental data for gas–solidflow through a straight pipe at different inclinations, Powder Technol.93 (1997) 253–260.

[59] D.J. Mason, P. Marjanovic, A. Levy, A simulation system for pneu-matic conveying systems, Powder Technol. 95 (1998) 7–14.

[60] D.J. Mason, A. Levy, P. Marjanovic, The influence of bends on theperformance of pneumatic conveying systems, Adv. Powder Technol.9 (3) (1998) 197–206.

[61] D.J. Mason, P. Marjanovic, Re-Visit of the fundamental definitionsof fluid-solids flow properties in freight pipelines, Proceedings ofthe 9th International Symposium on Freight Pipelines, Monterrey,Mexico, April 1998.

[62] P. Marjanovic, A. Levy, D.J. Mason, An investigation of the flowstructure through abrupt enlargement of circular pipe, Proceedingsof the 9th International Symposium on Freight Pipelines, Monterrey,Mexico, April 1998.

[63] P. Marjanovic, M. McGarvey, R.B. McKay, Development of labora-tory methodology to determine flow properties of organic pigmentpowders. Powder handling and processing, Trans. Tech. Pub. 10 (2)(1998) 151–154.

[64] M.G. Jones, P. Marjanovic, The influence of rotary valve air leakageon pneumatic conveying system performance, Proceedings of the23rd Powder & Bulk Solids Conference, Chicago, USA, May 1998,pp. 231–239.

[65] M.G. Jones, P. Marjanovic, The influence of rotary valve air leakageon pneumatic conveying system performance, J. Powder/Bulk SolidsTech. 2 (2) (1998) 3–10.

[66] M.G. Jones, P. Marjanovic, The optimisation of an existing pneumaticconveying system, J. Powder/Bulk Solids Technol. 2 (2) (1998) 12–16.

[67] P. Marjanovic, D. Geldart, J.L.R. Orband, Techniques for assess-ing powder flowability – a comparison, Proceedings of the WorldCongress on Particle Technology 3, Brighton, UK, July 1998.

[68] D.J. Mason, A. Levy, P. Marjanovic, The influence of bends onthe flow of gas-solids mixture trough pipelines, Proceedings of theWorld Congress on Particle Techn 3, Brighton, UK, July 1998.

[69] M.G. Jones, P. Marjanovic, D. McGlinchey, R. McLaren, Segregationin handling processes of blended industrial coal, Proceedings of the6th International Conference on Bulk Material Storage, Handlingand Transportation, Wollongong, Australia, September 1998.

[70] P. Marjanovic, M. McGarvey, R.B. McKay, Development of labora-tory methodology to determine flow properties of organic pigment


powders, Hopper & Silo Discharge: Successful Solutions. IMechE,London, UK, November 1998.

[71] E.A. Knight, M.G. Jones, P. Marjanovic, On-site measurement fortroubleshooting pneumatic conveying systems, Proceedings of theBulk Design Seminar, Sutton Coldfield, UK, December 1998.

[72] D.J. Mason, P. Marjanovic, Re-visit to the fundamental definitionsof fluid-solids flow properties in conveying pipelines, Proceedingsof the 2nd International Conference on Pneumatic and HydraulicConveying Systems. UEF Conf. Davos, Switzerland, June 1999.

[73] P. Marjanovic, E. McGee, Determination of powder flow propertiesusing different shear cells, Proceedings of the RelPowFlo 3, Pors-grunn, Norway, August 1999, pp. 151–158.

[74] M.G. Jones, P. Marjanovic, D. McGlinchey, D. Morrison, Investiga-tion of the discharge pattern of industrial coals from wedge shapedhoppers, Proceedings of the RelPowFlo 3, Porsgrunn, Norway, Au-gust 1999, pp. 543–550.

[75] P. Marjanovic, A. Levy, D.J. Mason, An investigation of the flowstructure through abrupt enlargement of circular pipe, Powder Tech-nol. 104 (1999) 296–303.

[76] P. Marjanovic, M. McGarvey, R.B. McKay, Determination of theinfluence of surface coating and particle size on flow properties oforganic pigment powders, Proceedings of the 3rd Israel Conferencefor Conveying and Handling of Particulate Solids, Dead Sea, Israel,vol. 1, May 2000, pp. 3.39–3.44.

[77] M.G. Jones, P. Marjanovic, D. McGlinchey, An investigation ofdegradation and segregation in typical coal handling processes, Pro-ceedings of the 3rd Israel Conference for Conveying and Handlingof Particulate Solids, vol. 1, The Dead Sea, Israel, May 2000, pp8.55–8.60.

[78] D.J. Mason, J. Li, P. Marjanovic, Numerical simulation of solidsfeeding in a gas-solids pneumatic transport system, Proceedings ofthe 3rd Israel Conference for Conveying and Handling of ParticulateSolids, vol. 2, The Dead Sea, Israel, May 2000, pp. 10.93–10.101.

[79] D. McGlinchey, P. Marjanovic, M. G. Jones, S. Cook, Particle seg-regation in pneumatic conveying lines, IMechE Conference Trans-actions, June 2000, pp. 331–340.

[80] M.G. Jones, A.G. Mason, P. Marjanovic, E. A. Knight, Bend Ef-fects in Pneumatic conveying, IMechE Conference Transactions, June2000, pp. 351–361.

[81] R.O. Ansell, P. Marjanovic, Hazardous substances – COSHH revis-ited, Powder Rep. 3 (4) (2000) 13–14.

[82] P. Marjanovic, E.A. Knight, J.R. Pugh, On-site measurement ofpneumatic conveying system performance: why, when, what and how,Proceedings of the 16th International Conference on Material Flow,Machines and Devices in Industry, Belgrade, Yugoslavia, December2000, pp. 20–25.

[83] J.S. Xiang, P. Marjanovic, Modelling and simulation for pyroflowtype circulating fluidised bed boiler, Proceedings of the Interna-tional Congress for Particle Tech PARTEC 2001, Nürnberg, Ger-many, March 2001.

[84] P. Marjanovic, Technology transfer between academia and industry– two-way street leading to mutual benefit and success, MHEABulk 2001 Technical Awareness Seminar, Manchester, UK, April2001.

[85] P. Marjanovic, E.A. Knight, J.R. Pugh, Benchmarking, optimisingand uprating of discontinuous pneumatic conveying system perfor-mance through on-site measurement, Proceedings of the 6th WorldCongress of Chemical Engineering, Melbourne, Australia, September2001.

[86] J. Li, P. Marjanovic, J.S. Xiang, E.A. Knight, An experimental tech-nique for the analysis of plugs travelling through pneumatic pipelinesusing pressure measurements, Proceeding of the 7th InternationalConference on Bulk Materials Storage, Handling and Transportation,Newcastle, Australia, October 2001, pp. 53–67.

[87] E. McGee, P. Marjanovic, L. Bates, Modifying flow behaviour inhoppers using inserts and novel wall profiles, Proceedings of the 7thInternational Conference on Bulk Materials Storage, Handling andTransportation, Newcastle, Australia, October 2001.

[88] J.S. Xiang, P. Marjanovic, Hydrodynamic model of gas-solid flowin circulating fluidised bed, Proceedings of the 7th InternationalConference on Bulk Materials Storage, Handling and Transportation,Newcastle, Australia, October 2001, pp. 825–832.

A review of the research work of Professor Predrag Marjanović

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