CRYOGENICSCRYOGENICS

PRESENTED BYPRESENTED BY

RAJKUMAR.GRAJKUMAR.G

VASUDAVEN.SVASUDAVEN.S

ABSTRACT

• Cryogenic Treatment is a material science and involves the process Cryogenic Treatment is a material science and involves the process of reducing the temperature of components over an extended of reducing the temperature of components over an extended period of time to extreme cold levels, usually slightly below -250°C. period of time to extreme cold levels, usually slightly below -250°C. The use of vapour compression circuit is to provide pre-cooling The use of vapour compression circuit is to provide pre-cooling emphasis the dependence of cryogenic cooling technology on emphasis the dependence of cryogenic cooling technology on refrigeration and the synergy between the two technologies. It is refrigeration and the synergy between the two technologies. It is apparent that gas compression and reduction in temperature as a apparent that gas compression and reduction in temperature as a result of throttling are common to both systems. The differences result of throttling are common to both systems. The differences are the thermodynamic properties of the working fluid and the are the thermodynamic properties of the working fluid and the temperature range of cycle. The significance of critical temperature range of cycle. The significance of critical temperature is also apparent. In the vapour compression cycle temperature is also apparent. In the vapour compression cycle shows all the processes occur below the critical temperature, as it shows all the processes occur below the critical temperature, as it typical for such cycles, and therefore condensation of the working typical for such cycles, and therefore condensation of the working fluid is possible simply by rejecting heat to a sink at a lower fluid is possible simply by rejecting heat to a sink at a lower temperature. By contrast, in the cryogenic cycle the temperature temperature. By contrast, in the cryogenic cycle the temperature of the working fluid only falls below the critical value in the of the working fluid only falls below the critical value in the throttling process. By this method, cryogenic treatment helps to throttling process. By this method, cryogenic treatment helps to reduce the temperature very low.reduce the temperature very low.

• KeywordsKeywordsAbsolute zero, Linde-Hampson system, Claude system, Absolute zero, Linde-Hampson system, Claude system,

various applications.various applications.

INTRODUTION• ““Cryogenics” stems from Greek and means "the production of Cryogenics” stems from Greek and means "the production of

freezing cold"; however the term is used today as a synonym for freezing cold"; however the term is used today as a synonym for the low-temperature state. It is not well-defined at what point on the low-temperature state. It is not well-defined at what point on the temperature scale refrigeration ends and cryogenics begins. the temperature scale refrigeration ends and cryogenics begins. Cryogenics typically involves a deep-freezing process, usually Cryogenics typically involves a deep-freezing process, usually one that takes object down below 240 degrees Fahrenheit and one that takes object down below 240 degrees Fahrenheit and changes the molecular alignment of the material structure. This changes the molecular alignment of the material structure. This change creates the new property. Cryogenic process has been change creates the new property. Cryogenic process has been researched and developed by universities and NASA since the researched and developed by universities and NASA since the mid-sixties after NASA discovered that deep space exploration mid-sixties after NASA discovered that deep space exploration vehicles had improved their structural integrity due to extended vehicles had improved their structural integrity due to extended exposure to cryogenic temperature. exposure to cryogenic temperature.

• The terms The terms cryogenicscryogenics,, cryobiology cryobiology are are frequently confused and given below:frequently confused and given below:

• CryogenicsCryogenics The branches of physics and engineering that involve the study The branches of physics and engineering that involve the study

of very low temperatures, how to produce them, and how of very low temperatures, how to produce them, and how materials behave at those temperatures.materials behave at those temperatures.

• CryobiologyCryobiology The branch of biology involving the study of the effects of low The branch of biology involving the study of the effects of low

temperatures on organisms (most often for the purpose of temperatures on organisms (most often for the purpose of achieving cryopreservation).achieving cryopreservation).

TYPES OF CRYOGENIC TREATMENTTYPES OF CRYOGENIC TREATMENT• SHALLOW CRYOGENICS,SHALLOW CRYOGENICS, made the objects to temperature of approximately -made the objects to temperature of approximately -

120o F.120o F.• FLOODING,FLOODING, takes the component to -120o F, then the chamber is flooded with takes the component to -120o F, then the chamber is flooded with

liquid nitrogen.liquid nitrogen.• DEEP CRYOGENICS TREATMENT,DEEP CRYOGENICS TREATMENT, Subjects the objects to the temperature of Subjects the objects to the temperature of

approximately -300o F.approximately -300o F. ABSOLUTE ZEROABSOLUTE ZERO Absolute zero is a temperature marked by a 0 entropy configuration. It is the Absolute zero is a temperature marked by a 0 entropy configuration. It is the

coldest temperature theoretically possible and cannot be reached by artificial or coldest temperature theoretically possible and cannot be reached by artificial or natural means. Temperature is an entropically defined quantity that effectively natural means. Temperature is an entropically defined quantity that effectively determines the number of thermodynamically accessible states of a system determines the number of thermodynamically accessible states of a system within an energy range. Absolute zero physically possesses quantum mechanical within an energy range. Absolute zero physically possesses quantum mechanical zero-point energy. Having a limited temperature has several thermodynamic zero-point energy. Having a limited temperature has several thermodynamic consequences; for example, at absolute zero all molecular motion does not consequences; for example, at absolute zero all molecular motion does not cease but does not have enough energy for transference to other systems, it is cease but does not have enough energy for transference to other systems, it is therefore correct to say that at 0 Kelvin molecular energy is minimal. In addition, therefore correct to say that at 0 Kelvin molecular energy is minimal. In addition, any particle with zero energy would violate Heisenberg's Uncertainty Principle, any particle with zero energy would violate Heisenberg's Uncertainty Principle, which states that the location and momentum of a particle cannot be known at which states that the location and momentum of a particle cannot be known at the same time. A particle at absolute zero would be at rest, so both its position, the same time. A particle at absolute zero would be at rest, so both its position, and momentum (0), would be known simultaneously.and momentum (0), would be known simultaneously.

• By international agreement, absolute zero is defined as precisely 0 K on the By international agreement, absolute zero is defined as precisely 0 K on the Kelvin scale, which is a thermodynamic (absolute) temperature scale, and Kelvin scale, which is a thermodynamic (absolute) temperature scale, and −273.15° on the Celsius scale.[1] Absolute zero is also precisely equivalent to 0 −273.15° on the Celsius scale.[1] Absolute zero is also precisely equivalent to 0 R on the Rankine scale (same as Kelvin but measured in Fahrenheit intervals), R on the Rankine scale (same as Kelvin but measured in Fahrenheit intervals), and −459.67° on the Fahrenheit scale. and −459.67° on the Fahrenheit scale.

• PRODUCTION OF LOW TEMPERATUREPRODUCTION OF LOW TEMPERATUREThe following methods are involved to produce the low The following methods are involved to produce the low

temperature in cryogenics:temperature in cryogenics:• Heat conductionHeat conduction: It is a relatively simple concept to understand. When : It is a relatively simple concept to understand. When

two bodies are in contact, heat flows from the body with the higher two bodies are in contact, heat flows from the body with the higher temperature to the body with a lower temperature. Conduction can temperature to the body with a lower temperature. Conduction can occur between any and all forms of matter, whether gas, liquid, or solid. occur between any and all forms of matter, whether gas, liquid, or solid. It is essential in the production of cryogenic temperatures and It is essential in the production of cryogenic temperatures and environments.environments.

• Evaporative coolingEvaporative cooling: : Humans are familiar with this process because it Humans are familiar with this process because it is a mechanism in which our bodies lose heat. Atoms and molecules in is a mechanism in which our bodies lose heat. Atoms and molecules in the gaseous state are moving faster than the atoms and molecules in the gaseous state are moving faster than the atoms and molecules in the liquid state. Add heat energy to the particles in a liquid and it will the liquid state. Add heat energy to the particles in a liquid and it will become gaseous.become gaseous.

• The Joule-Thomson effectThe Joule-Thomson effect: : It was discovered by the English Physicist It was discovered by the English Physicist James Prescott Joule, William Thomson and Lord Kelvin, in 1852. They James Prescott Joule, William Thomson and Lord Kelvin, in 1852. They found, for example, that allowing a gas to expand very rapidly causes found, for example, that allowing a gas to expand very rapidly causes its temperature to drop dramatically. Reducing the pressure on a gas its temperature to drop dramatically. Reducing the pressure on a gas accomplishes the same effect. accomplishes the same effect.

• The Joule-Thomson effect is an important part of our lives today, even The Joule-Thomson effect is an important part of our lives today, even though we may not be aware of it. Ordinary house hold refrigerators though we may not be aware of it. Ordinary house hold refrigerators and air conditioners operate on this principle. First a gas is pressurized and air conditioners operate on this principle. First a gas is pressurized and cooled to an intermediate temperature by contact with a colder gas and cooled to an intermediate temperature by contact with a colder gas or liquid. Then the gas is expanded, and its temperature drops still or liquid. Then the gas is expanded, and its temperature drops still further. The heat needed to keep this cycle operating comes from the further. The heat needed to keep this cycle operating comes from the inside of the refrigerator or the interior of a room, producing the desired inside of the refrigerator or the interior of a room, producing the desired cooling effect.cooling effect.

• METHODS OF LIQUIFICATION OF AIRMETHODS OF LIQUIFICATION OF AIR• Linde’s system also known as hampson system.Linde’s system also known as hampson system.• Claude’s system.Claude’s system.

LINDE’S SYSTEMLINDE’S SYSTEM

• Clean dry air is taken from the atmosphere and is Clean dry air is taken from the atmosphere and is compressed up to 200 bar.compressed up to 200 bar.

• The high pressure enters into counter flow air to air The high pressure enters into counter flow air to air heat exchanger and is then throttled to atm - heat exchanger and is then throttled to atm - pressure.pressure.

• The J-T cooling up to expansion causes a lowering of The J-T cooling up to expansion causes a lowering of temperature and this cool air is passed through heat temperature and this cool air is passed through heat exchanger where it cools the incoming high section.exchanger where it cools the incoming high section.

• Thus the temperature at the valve is progressively Thus the temperature at the valve is progressively lowered until the liquefaction temperature is reached.lowered until the liquefaction temperature is reached.

LINDE’S SYSTEMLINDE’S SYSTEM

T-S DIAGRAM (Linde’s T-S DIAGRAM (Linde’s system)system)

PROCESS1-2: Compression2-3: Pre-cooling of air by pre cooling circuit3-4: Pre-cooling of air by Heat exchanger4-5: Throttling process5’-6: Process in evaporator

CLAUDE’S SYSTEM CLAUDE’S SYSTEM DIAGRAMDIAGRAM

CLAUDE’S SYSTEMCLAUDE’S SYSTEM

• Claude’s system yields more efficient cycle than Claude’s system yields more efficient cycle than Linde’s systemLinde’s system

• The expansion through an expansion valve is an The expansion through an expansion valve is an irreversible process.irreversible process.

• In Claude’s system energy is removed from the In Claude’s system energy is removed from the gas stream by using an expansion engine or gas stream by using an expansion engine or expander.expander.

• The expansion process is isentropic and much The expansion process is isentropic and much lower temp is attained then isenthalpic expansionlower temp is attained then isenthalpic expansion

• In Claude’s system the gas is first compressed to In Claude’s system the gas is first compressed to pressure of the order 4 Mpa.pressure of the order 4 Mpa.

T-S DIAGRAM (Claude’s T-S DIAGRAM (Claude’s system)system)

How Claude’s system is more efficient than Linde’s system

The advantage of the Claude’s system is, it operates at low compression ratio compared with linde’s process. Secondly the temperature of air before coming to the expansion valve in Claude system is lower than the Linde system.

APPLICATION OF APPLICATION OF CRYOGENICSCRYOGENICS

– Aerospace-cryogenic enginesAerospace-cryogenic engines– Medical Field Medical Field – Manufacturing field Manufacturing field – Electronics FieldElectronics Field– Fuels research.Fuels research.

CRYOGENIC ENGINES IN CRYOGENIC ENGINES IN AEROSPACEAEROSPACE

• The first operational Cryogenic Rocket Engine is the 1961 NASA design The first operational Cryogenic Rocket Engine is the 1961 NASA design the the RL-10RL-10 LOX LH2 rocket engine. LOX LH2 rocket engine.

• The upgraded cryogenic second-stage Pratt & Whitney RL10B-2 engine The upgraded cryogenic second-stage Pratt & Whitney RL10B-2 engine is based on the 30-year heritage of the reliable RL10 engine.is based on the 30-year heritage of the reliable RL10 engine.

• At Mahendragiri in Tamil Nadu, is the Liquid Propulsion System Centre At Mahendragiri in Tamil Nadu, is the Liquid Propulsion System Centre [LPSC]. Here work on developing India’s own cryo - engines has been [LPSC]. Here work on developing India’s own cryo - engines has been quietly moving. The system involves materials working at 250 deg quietly moving. The system involves materials working at 250 deg below zero and pumps at speeds of 40,000 rpm. There are also below zero and pumps at speeds of 40,000 rpm. There are also complex metering, monitoring, integrating technologies involved. The complex metering, monitoring, integrating technologies involved. The engines are required to fire for about 700 seconds during the final stage engines are required to fire for about 700 seconds during the final stage of a launch providing 7 tones of thrust..of a launch providing 7 tones of thrust..

• The Engine works on ‘Staged Combustion Cycle’ with an integrated The Engine works on ‘Staged Combustion Cycle’ with an integrated turbo pump running at around 42,000 rotations per minute (rpm). It is turbo pump running at around 42,000 rotations per minute (rpm). It is also equipped with two steering engines developing a thrust of 2 kN also equipped with two steering engines developing a thrust of 2 kN each to enable three-axis control of the launch vehicle during the each to enable three-axis control of the launch vehicle during the mission. Another unique feature of this engine is the closed loop control mission. Another unique feature of this engine is the closed loop control of both thrust and mixture ratio, which ensures optimum propellant of both thrust and mixture ratio, which ensures optimum propellant utilization for the mission.utilization for the mission.

CRYOGENICS IN MEDICAL CRYOGENICS IN MEDICAL FIELDFIELD

CRYOSURGERYCRYOSURGERY• Cryosurgery (also called cryo therapy) is the use of extreme cold Cryosurgery (also called cryo therapy) is the use of extreme cold

produced by liquid nitrogen (or argon gas) to destroy abnormal tissue.produced by liquid nitrogen (or argon gas) to destroy abnormal tissue.• Cryosurgery is used to treat external tumors, such as those on the skin.Cryosurgery is used to treat external tumors, such as those on the skin.• For internal tumors, liquid nitrogen is circulated through a hollow For internal tumors, liquid nitrogen is circulated through a hollow

instrument called a cryoprobe.instrument called a cryoprobe.• Cryosurgery has been used for many years in the treatment of skin Cryosurgery has been used for many years in the treatment of skin

cancercancer

BENEFITS OF CRYOSURGERYBENEFITS OF CRYOSURGERY• Cryosurgery is very effective and is less expensive than other Cryosurgery is very effective and is less expensive than other

treatment. It can be done in your health care provider’s office treatment. It can be done in your health care provider’s office and an anesthesia is not necessary.and an anesthesia is not necessary.

• The treatment can be safely repeated and may be used along The treatment can be safely repeated and may be used along with standard treatments such as surgery, chemotherapy, with standard treatments such as surgery, chemotherapy, Harmon therapy and radiation.Harmon therapy and radiation.

• It can be used for patients who are not good candidates for It can be used for patients who are not good candidates for conventional surgery because of their age or other medical conventional surgery because of their age or other medical condition.condition.

• It is used to treat skin lesions such as freckles (for cosmetic It is used to treat skin lesions such as freckles (for cosmetic reasons), hemorrhoids and some skin cancers reasons), hemorrhoids and some skin cancers

CRYOGENICS IN MANUFACTURING CRYOGENICS IN MANUFACTURING FIELDFIELD

• Cryogenic treatment works on Reamers, Tool bits, Tool Cryogenic treatment works on Reamers, Tool bits, Tool punches, Carbide Drills, Carbide Cutters, Milling Cutters, punches, Carbide Drills, Carbide Cutters, Milling Cutters, Files, Knives, Reciprocating Blades, Dies and cutting tools.Files, Knives, Reciprocating Blades, Dies and cutting tools.

• Stress relives ferrous and non ferrous castings and Stress relives ferrous and non ferrous castings and forgings for enhanced dimensional stability and surface forgings for enhanced dimensional stability and surface finish upon finish machining.finish upon finish machining.

CRYOGENICS IN ELECTRONICS CRYOGENICS IN ELECTRONICS FIELDFIELD

The super conducting electronic devices like SQUID (Super conducting The super conducting electronic devices like SQUID (Super conducting quantum interference device) are used in sensitive digital magnetometers quantum interference device) are used in sensitive digital magnetometers and voltmeters.and voltmeters.

Zero friction bearings use magnetic field instead of oil or air, derived from the Zero friction bearings use magnetic field instead of oil or air, derived from the Meissner effect associated with super conductivity.Meissner effect associated with super conductivity.

Super conducting electric motors are constructed approaching zero electric Super conducting electric motors are constructed approaching zero electric loses.loses.

CONCLUSIONCONCLUSION

Refrigeration and cryogenic cooling technology Refrigeration and cryogenic cooling technology share a common history and there are many similarities share a common history and there are many similarities in the underlying thermodynamics. The significant in the underlying thermodynamics. The significant differences lie in the temperature range of interest and differences lie in the temperature range of interest and the properties of the working fluids. the properties of the working fluids.

Whilst it is most unlikely that cryogens can ever Whilst it is most unlikely that cryogens can ever replace more familiar refrigeration technology for ‘high’ replace more familiar refrigeration technology for ‘high’ temperature cooling, there may be niche applications temperature cooling, there may be niche applications where they can offer an interesting alternative. where they can offer an interesting alternative.

REFERENCESREFERENCES

• Cryogenic engines, http://en.wikipedia.orgCryogenic engines, http://en.wikipedia.org

• Cryogenic engines, www.astronautix.comCryogenic engines, www.astronautix.com

• Cook P. & Richatdson R.N., Cryogenic Cook P. & Richatdson R.N., Cryogenic safety manual, see www.ior.org.uksafety manual, see www.ior.org.uk

• GIST (Previously BOC Transhield), see GIST (Previously BOC Transhield), see www.gistworld.comwww.gistworld.com

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