Millennium City Center - Budapest University of Technology ... · Millennium City Center A formerly...

Grand Prix – Industria 2004

Budapest University of Technology and Economics Department of Fluid Mechanics H-1111 Budapest, Bertalan L. u. 4-6. www.ara.bme.hu

Millennium City Center

A formerly unbuilt, but very good located quarter of Budapest was decided to be

utilized by creating a new center of culture. Before starting the construction works of the Millennium Center, extensive social discussion was about the potential threat for the neighboring locations in terms of increased air pollution due to the higher traffic and the coverage effect of the new buildings.

The investors agreed with the stakeholders – in first line with the representatives of the leading environmental organizations – to hire the Department for investigating the effects of the new buildings on the surrounding area in terms of air pollution.

- 1:500 model scale - Implementation of a grille and roughness elements to simulate the atmospheric boundary layer - Highly detailed wooden model of 200 buildings - Taking into consideration the level of Danube - Simulation of the traffic by means of line sources on the main roads and on the bordering two bridges with total length equivalent to 2 km in real life - Implementation of a “unit vehicle” for taking into account the structure of traffic - Investigation of 5 characteristic wind flow directions - Implementation of 16 + 8 measurement points - Using of the method “sand erosion” for investigation of flow through



Shopping Mall Mammut

A new shopping mall was started to be built in a very densely populated area of

Budapest. The expected increase in traffic due to the new buildings resulted serious concerns in the public about the air quality in the surroundings. A further problem was expected from the effect of the new building on the wind directions, and hence on the through ventilation of the area.

Our task was to predict the effects of the new building on the air pollution in its environment.

- 1:500 model scale, modeled area of a diameter of 1 km - Buildings and plants were modeled more detailed than the international practice - Application of a grid and roughness elements to simulate the atmospheric boundary

layer - Investigation of 4 wind directions - Application of methane tracer gas for line sources - Flame ionization measurement of the concentration - Weighting of results based on wind direction and velocity probabilities



FIOBCo Celebration Hall in Dubai

In case of light construction like tent roof the main component of the load acting

on the construction is the wind force. Concerning the standard values of this force the literature is very limited, and the values to be applied are strongly depending on the shape of the roof and the installation environment. The design based on standards results in many cases in unnecessarily oversized and expensive constructions.

The aim of the project was in this case to predict the wind force acting on this Celebration Hall.

- 1:300 model scale - Measurement in 200 points - Investigation of 6 wind directions



4th Terminal of Dallas Airport

In the construction plans of the 4th terminal of Dallas Airport a tent roof

construction of a large extension was included. Concerning the required stiffness of the tent roof and the holding elements it is crucial to know the forces resulted from wind pressure. In this case however, the tent roof is situated between two large buildings, thus, the determination of wind forces based on experience was not possible.

The aim of the project was to determine the pressure distribution and thus the resulting wind forces.

- Model scale of 1:200 - Tent model made of 2 mm thick plastic plate - Investigation of 6 characteristic wind directions - Implementing oil mist, laser plane and a special camera for examination of the flow pattern



Open Air Theater in Las Vegas

The open air theater in Las Vegas is situated in a windy area, therefore the wind

force acting on the tent roof of the theater gained a special importance. The prediction of wind forces based on experiences was hindered by unusual shape and location of the tent, namely that a large, box shaped stage house is connected to it on one side, which strongly influences the flow conditions.

The aim of the investigations was to determine the wind forces acting on the tent roof.

- 1:80 model scale - Separate measurement of internal and external pressure distribution - Resin composite model construction with 2 mm thickness - 60 measurement points each side

45°



nTelos Pavilion in Portsmouth

The Harbor Center in Portsmouth (Virginia) is situated on the seaside in the

west coast of USA. The open air theater in this center has a tent roof. The stress analysis of the tent roof requires the knowledge of a detailed wind load distribution.

The aim of the investigations was to determine the wind forces acting on the tent roof, in order to establish a solid basis for stress analysis.

- 1:150 model scale, Ø300 m of the area is modeled - Tide taken into consideration: modeling two sea levels at relevant wind directions - Investigation of different tent designs - Modeling 6 different wind directions - A sandwich construction in order to measure the pressure simultaneously on both sides of the membrane - 2x48 measurement points - Sampling with 400 Hz in 20 second time frames



Ice Stadium in Essen

The tent roof of the ice stadium in Essen, Germany, is relatively simple, but its

size is outstanding. Regarding the wind force measurement, the effects of the three peaks on each other make the investigations especially interesting.

The aim of the investigation was to determine the wind force distribution of the tent roof, in order to back the stress analysis and design process.

- 1:60 model scale - 60 measurement points - Variable installation of pressure measurement points to measure internal and external pressure - Numerical simulation of wind forces resulted in pressure distributions agreed quite well with measured ones


Flow Conditions on and Around the Budapest Sportsarena

On buildings with an extremely large outer surface, like the new Budapest

Sportsarena, the force resulted from the wind pressure is crucial concerning the stiffness of the construction. However, the role of flow conditions is also important regarding the wind comfort of the surrounding of a building, i.e. in the positioning of the various outside objects like seating or a coffee-bar.

Thus, the aim of our project was to determine the flow conditions around the considered building.

- Implementation of turbulence generators on horizontal edges - 120 pressure outlets - Data acquisition on 200 Hz, in 10 seconds time frames - Implementation of sand erosion method - Oil mist and laser plane for visualization of the flow pattern - Special camera with a high time resolution




Fire Propagation in the Budapest Sportsarena

Fire security of communal buildings with high seating capacity is a crucial factor

of design. Since the ancestor of the new Budapest Sprotsarena was totally destroyed in a fire, the constructors of the new building put a further increased emphasis on fire security.

In the project, a model fire was implemented in a numerical simulation. The location and the intensity of this fire were determined according to current rules of law. The effectiveness of the smoke ventilation system was examined in order to guarantee the smokeless air in the near of the audience until the evacuation is completed.

- Implementation of a 2 and 3 dimension simulation model at the same time - Modeling fire as a heat and carbon-dioxide source - Propagation velocity of constant boundary layer - Constant intensity of fire in space and time - Exponentially increasing source term



Ventilation of the Budapest Sportsarena

When designing the ventilation system of a sports hall with large capacity the

double challenge of the heat produced by high number of audience and expectations from the side of technical sports has to be tackled. For example on a figure skating competition the air 1.5 m above the ice-rink must not be colder than 18 ºC, while in case of a table-tennis competition there are strict regulations about the maximum air speed affordable around the tables.

In this project the intended design of ventilation system was simulated, and among others the effect of changes in allocation and outflow directions of air intake nozzles and implementation of variable nozzles was examined.

- Detailed modeling of the entire hall - Examination of temperature and air velocity requirements - Evaluation of the intended constructional changes



National Opera House

The human comfort level concerning the indoor air conditions basically depends

on flow conditions, air temperature and humidity, and radiating heat. Our Department has investigated these factors by means of the commercial code FLUENT in the National Opera House in Budapest. Based on the results of this project the necessary modifications on the ventilation systems can be determined in case of a reconstruction of the building.

- Modeling the whole internal space - Full simulation of the air inlet and air outlet points - Investigation of the flow pattern and the heat distribution in case of different scenarios for ventilation configuration



Concert Hall of National Philharmonics

When designing the ventilation system of theaters or concert halls, the

conflicting problems of exhausting the heat produced by the high number of audience and the usually high performance lighting elements, and the requirement of low noise and low air velocities in ventilation mean an increased technical challenge.

In this project the air flow in the concert hall of National Philharmonics to be built was simulated. The ventilation system and the effect of ventilation on the real comfort perceiving was investigated, in order to support the optimal placing of intake and exhaust nozzles.

- Detailed modeling of the full auditorium - Simulation of the natural convection created by the heat produced by the audience and lighting elements - Checking of operation of ventilation system



Aula of a Bank Building

Flow conditions of a large hall, like an aula or atrium are very important if the

considered people are permanently in the hall. The technical complexity of the problem is increased if the boundary walls of the hall are made of glass – in this case the consideration of “cold radiation” means an important additional aspect in design.

In this project by using computer simulation we investigated the internal flow conditions of a 3 floor, one interior aula to be used also as an office building, in order to determine the comfort of the floors open to the atrium.

- Investigation of comfort parameters in the hall - Calculations to decide if an application of a wind curtain at the entrance is necessary - Determining the effects of “cold radiation” - Calculation of the heat losses resulted by the automatic doors



Ventilation of Office Buildings

The design of ventilation systems for offices raises a number of technical

challenges related to fluid mechanics. Beside the performance of ventilation system, number, size and allocation of intake nozzle units are also important aspects to be considered. Through appropriate investigation of these challenges it is possible to assure the heat and air velocity comfort of people working in the office, and it can be avoided that the intake air leaves the room through hydrodynamic shortcuts without executing its desired effect.

To support the design a 3D numerical simulation of the flow was carried out, through which the air flow characteristics like temperature, velocity, moisture belonging to different configurations of the ventilation system can be examined.

- Displaying the path of intake air with consideration of residence time of intake air - Testing different configuration to obtain optimal ventilation (Velocity and direction of air, size, number and allocation of air intake nozzles) - Accurate modeling of air flow conditions in complicated spaces



Ventilation of Industrial Halls

The applied manufacturing technologies require in many cases additional

considerations when designing ventilation systems for industrial halls. The heat load of such halls is in most of the cases high due to the equipment being operated there. Beside the comfort parameters of employees it is usually necessary to take into consideration the additional requirements of the applied technology (e.g. the strict temperature or air velocity requirements of a specific manufacturing technology).

In the investigated industrial hall 3 MW of heat performance is produced due to the special technology applied. The affordable air velocity around the machines is strictly limited, because a higher velocity would negatively influence the quality of the products. In order to support the design of ventilation system we created a 3D numerical simulation, by means of which the flow resulted in the different configuration can be examined accurately.

- Simulation of large heat load - Investigation of undesired air velocities - Determination of temperature distribution for evaluation of working environment comfort



Bridge of the Highway M8

The new bridge of the highway M8 currently under development is the largest of

its kind in the world. This fact just attracted further attention on the very important question of wind forces acting on a bridge construction. The installation environment and the shape of the bridge determine the sensitivity of the construction to wind forces.

The aim of the project was to map the force and torque acting on the bridge in case of typical extreme wind loads, and the typical periodical wind structures resulting oscillations.

- Section model with a model scale ratio of 1:70 - Aluminium base structure, highly detailed elaboration - Implementation of Large-Eddy method in case of numerical simulation



GSM Cell Phone Towers

The design of a new GSM cell phone tower is based on model family approach.

The critical load of the construction arises from wind forces due to its height. Each model of the model family is constructed according to standardized calculation methods, although which contain the directives only very roughly.

The aim of the investigation supplied for a leading Hungarian mobile phone supplier was to determine the actual load resulting from the wind force on a section model of a GSM tower.

- Model scale of 1:6 - Pre-experiments for mapping the Reynolds effect - Creating the conditions for a 2 dimension flow - Benchmarking the measurement results with the original calculation based on the directives of the standard - Force sampling on a 500 Hz frequency



Smoke Deflection in a Steel Converter

During the steel manufacturing process with a converter technology a large

amount of hot crude iron is split on a great amount of waste steel. The process is accompanied by intensive emission of hot tracer gas. Exhaustion of this gas is fairly complicated due to lack of space in the installation environment. A further challenge arises from the characteristic that the charge arises in impulses and is differing from the continuous load in orders of magnitude.

The project was aiming the optimization of suction hood and ventilation through detailed investigation of the evolved flow by means of laboratory measurements and numerical simulation.

- Validation by means of model experiments - Consideration of natural convection due to differences in density - Determination of suction efficiency with consideration of operation parameters



Heat-Treatment Furnace

In case of heat-treatment of aluminium cylinders the temperature level desired

for recrystallization approaches the melting point of the material, therefore the equal distribution of heat load is crucial in order to avoid melting. For achieving best results, a warm-up period must be followed by particularly slow heat treatment with the most equal possible heat treatment.

The aim of the project was to optimize the air flow in the furnace and to find the best configuration of the nozzles.

- Calculation of heat transfer in a turbulent flow - Non-stationary heat transfer - Validation of the temperature change in the considered object



Pharmaceutical Fermenter

The task of a pharmaceutical fermenter is to introduce and mix the desired

amount of nutritive and oxygen necessary for the development of bacteria. It is critical regarding the process to introduce enough oxygen without causing a level of sheer stress in the mixture which might damage the bacteria.

The aim of the investigation was to detect the critical places concerning oxygen supply, and the optimization of the method of air introduction.

- Two phase flow - Implementation of a 2 and 3 dimension flow model at the same time - Involvement of the moving mixing vane into the model - Calculation of the mechanical load



Flows in Swimming Pools

When designing or redesigning a swimming pool the most important goal is to

guarantee high water quality. The most important – measurable – parameters are the concentration of free active chlorine, and the temperature and residence time of water. The flow field of a pool can be investigated by means of numerical simulation, thus the unfavorable dead spaces can be found, and the spatial distribution of relevant water quality values can be determined.

The aim of such a project is to support the design or redesign efforts through determination of flow characteristics resulted in different variations.

- Examination of “show” design elements (critical velocities, forces resulted from flows acting on people in pool)

- Visualization of vertical and horizontal vortices - Investigation of processes in filters - Ventilation and air-conditioning (dehumidifying, moisture control over the pool

level, energetic optimization of ventilation system) - Wind load of and wind comfort in the outdoor area



Exhaust Pipe of a Passenger Car

In the regulated catalytic converter located in the exhaust pipe of a passenger

car exothermal catalytic reaction occurs. The quantity of heat produced during this process strongly depends on the flow velocity in the converter. Overheating might damage the converter, thus, the even thermal load is crucial regarding the endurance, i.e. the flow in the converter must be as even as possible. The computational calculation is complicated through the conditions that the installed configuration consists of amorphous pipes and the catalytic body of the converter is made of a material with porosity depending on flow direction.

The aim of the calculation was determining the velocity distribution and the heat load distribution.

- Direct implementation of the CAD model - An approximately anisotropic porous zone - Compressible medium - Locally trans-sonic flow - Validation by means of available measurement data



Side Channel Fuel Pump

Several million pieces of side channel fuel pumps are built into passenger cars.

Proper functioning of these parts is crucial concerning the operation of the vehicle. The extent of electric power used by these pumps is one of the determining loads regarding the electric network of cars. Despite it, there is a lack of exact knowledge about their operation. However, it would be necessary to discover the reasons of its very low efficiency and to establish a theoretical background for being able to reach significant development goals.

The aim of the numerical simulation was the investigation of the flow field in a fuel pump manufactured by Visteon, and the providing of proposals for development.

- Determining the theory of operation - Geometrical modeling - Numerical simulation with cavitations taken into consideration - Validation based on measurements



Flow Visualization

Qualitative characterization and visualization of flows can be performed via

common flow visualization techniques. Special optical methods like concentration measurement via laser light sheet technique or discomfort parameter tests via sand erosion method are also available and used at the Department.

- Flow visualization via laser and light sheet - Flow tracer particles: professional oil smoke generator SAFEX /Normal and Blitz type fog fluid/ - Sand erosion test - Image recording and processing: CCD camera and software LaVision - Analogue / digital photo + video documentation equipments



Passenger Compartment Air Intake Units

The manufacturer of the air intake units need to prove the reliability and

effectiveness of its product in terms of air flow path and distribution towards the car industry contractor. Therefore the passenger compartment air intake units are tested aiming strong requirements of reaching the so-called EYE-ELLIPSE and H-POINT of the driver both in vertical and horizontal distribution and path of the air flow. The investigation can be performed e.g. by flow visualization tests. The model control panel of the passenger compartment includes 2 air intakes of the driver side. Oil smoke generator is used to seed the flow separately and laser light sheet for illumination of the air flow with oil smoke tracers. Based on the photographic and video documentation the test results are analyzed and air flow images are graphically fitted into the passenger compartment drawing.

- Vertical/horizontal laser sheet investigation - Laser sheet flow visualization - Photo and video visualization



Ultrasonic Type Flow Rate Measuring

The installation of an ultrasonic type flow measurement device after an electrostatic filter featuring secondary flows in power plants requires a high attention, since it is strictly expected that the data for volume flow and emission control systems are representative. This means that the measured data of velocity and dust concentration must be equal to the average of the considered flow cross section.

During the investigation we examined the phase flow of the hot exhaust gas and dust particles between the outlet of the electro filter and the inlet of the suction ventilator, and based on the results we proposed the correct device position capable of supplying representative values.

- Mapping of comprehensive flow patterns - Choosing of positions capable of supplying representative values - Placing the measurement device



Calibration

The von Kármán Tódor Wind Tunnel Laboratory at the Department of Fluid Mechanics provides a wide range of probe calibration facilities in the field of fluid mechanics. Four different wind tunnels are available for air flow test probes calibration in the range of v=0-60m/s: horizontal flow, open test section recirculation type (∅d=2.6m, vmax=60m/s); vertical flow, open test section recirculation type (∅d=1.4m, vmax=35m/s); atmospheric boundary layer /ABL/ type closed test section (1.5×2m, vmax=22m/s); National Physical Laboratory /NPL/ type closed test section (0.5×0.5m, vmax=15m/s).

A rotating head probe stand in closed test room is also available for low velocity range (v=0÷1m/s). Experimental facilities, equipments: Laser Doppler Anemometer /ILA/, 1-2-3D CTA hotwires /DANTEC/, Heated Sphere Anemometers /TESTO/, exemplified Betz-type manometer, Pitot-static tubes, etc.

- air flow probe calibration (e.g. ducted vane anemometer, hotwire probe, heated sphere probe) - pressure loss characteristic curve of industrial filter elements - testing and measuring of complex flow systems - wind speed/rpm characteristic curve measurement of fans; torque/rpm characteristic curve of unique design wind turbine; wind tunnel test of warning triangle, etc.



Induction System of an IC Engine

The correct configuration of induction systems is imperative for the IC engines

as it greatly affects the performance and emission. Properly formed resonance chambers in the induction system provide optimal performance in broader rpm ranges, while retaining low emissions and fuel consumption.

The aim of the project was to determine the correct configuration of the resonance chambers and the connecting pipes in a V-6 gasoline engine.

- Dynamic analysis on the whole rpm range - Investigation of the λ (excess air) coefficient - Investigation of non-measurable and hard-to-measure system variables - Global analysis of different physical subsystems (thermal, pneumatic, mechanical) - Sensitivity analysis of system parameters - FFT and linear analysis

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Pneumatic Air Supply System

A pneumatic air supply system is the foundation of pneumatic circuits. Usually

one compressor supplies the air for several pneumatic circuits. A typical example is a commercial vehicle: one compressor provides supply for the pneumatic brake systems of a trailer-truck and its trailer-coach. Therefore it is essential for the pressure distribution device to be able to protect the other connected circuits when one of them fails, e.g. become ruptured or generates excessive pressure oscillations.

The aim of the project was to determine the changes in the system operation if the manufacturer applies some cost-reducing modifications on the pressure distribution device, and to propose corrections to retain proper system operation.

- Dynamic analysis - Retain proper system operation even after constructional modifications - Investigation of non-measurable system variables - Global analysis of different physical subsystems (pneumatic, mechanical, electrical) - Sensitivity analysis of system parameters - FFT and linear analysis



Electronic Air Control System

A pneumatic air supply system is the foundation of pneumatic circuits. It should

provide controlled loading process, correct level of pressurization, proper filtration and dehumidification of the pressurized medium, regeneration of the filter element at appropriate intervals, and controlled unloading process in case of a general system inspection.

The aim of the project was to reveal the causes of the oscillation that appeared during certain operational states, and to propose system parameter alterations in order to eliminate this phenomenon.

- Dynamic analysis - Investigation of oscillations with FFT and linear analysis - Investigation of non-measurable system variables - Global analysis of different physical subsystems (pneumatic, mechanical, electrical) - Sensitivity analysis of system parameters



Electro-Pneumatic Brake System

Electro-pneumatic brake systems provide such features for commercial vehicles

that can be found only on recent automobiles. These may include anti-block systems (ABS) to prevent wheels from locking during braking, traction control systems (ASR) to ensure that none of the wheels on the driven axle spin during acceleration, and electronic stability control systems (ESP) to correct an unstable driving condition by applying precise braking action to the individual wheels.

The aim of the project was to determine optimal parameters in order to retain – or even enhance – the braking system operation after applying certain size- and mass-reducing modifications on an electro-pneumatic brake valve.

- Dynamic analysis - Retain correct system operation even after constructional modifications - Investigation of hardly measurable system variables - Global analysis of different physical subsystems (pneumatic, mechanical, electrical) - Sensitivity analysis of system parameters - FFT and linear analysis



Dual Cycle Brake Chamber

Nowadays, safety regulations of commercial vehicles specify that pneumatic

brake systems should provide appropriate – albeit reduced – deceleration even if one of the brake circuits become ruptured. Therefore it is necessary to develop special brake devices that are still able to generate adequate brake force even if the primary actuator mechanism is unable to operate due to the pressure loss in the main pneumatic circuit.

The aim of the project was to reduce the response time of the secondary actuator mechanism of a dual cycle brake chamber.

- Dynamic analysis - Reduce the response time of the secondary actuator mechanism - Investigation of non-measurable system variables - Global analysis of different physical subsystems (pneumatic, mechanical, electrical) - Sensitivity analysis of system parameters - FFT and linear analysis

Millennium City Center - Budapest University of Technology ... · Millennium City Center A formerly...

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