Cryogenics Introduction Overview and Applications Prof Anand Bhatt

Cryogenics Introduction, Overview and Applications Prof. Anand Bhatt APME, IT, NU

What is Cryogenics? ● ● ● Cryo means Icy cold and Genics means to produce. It is that branch of Engineering science which deals with the production of low temperature below 123 K (-150 degree celcius). C=K+273 It also deals with the different phenomenas occuring at ultra low temperature. It explains some shocking and fascinating facts which occur only at ultra low temperature.

Important Mechanical Parameters ● Pressure (P) ● Stress (σ) ● Temperature (T) ● Strain (ε) ● Volume (V) ● Yield Stress (σy) ● Internal Energy (U) ● Ultimate Stress(σu) ● Heat (Q) ● Young Modulous (E) ● Enthalpy (H) ● Heat Engine ● Entropy (S) ● Refrigerator ● Specific Heat (Cp) ● Efficiency & C. O. P ● Thermal Conductivity (k) ● Sensible Heat ● Laws of Thermodynamics ● Latent Heat

Syllabus • Low Temperature Properties – Mechanical, thermal, electrical and magnetic properties of engineering materials, properties of cryogenic fluids. • Gas Liquefaction Systems – Thermodynamically ideal system, Joule Thomson effect adiabatic expansion, simple, pre-cooled and dual pressure Linde Hampson systems, Claude system, Kapitza system, Heylandt system, other liquefaction system using expanders, comparison of liquefaction systems, liquefaction systems for hydrogen and helium • Cryogenic Refrigeration Systems – Ideal isothermal and isobaric source systems, Joule Thomson systems, pre-cooled Joule Thomson system, expansion engine system, Philips refrigerator, G M refrigerator, Pulse Tube refrigerator. • Measurement Systems for Low Temperatures – Temperature, pressure flowrate and liquid level measurement at low temperatures. • Cryogenic Fluid Storage – Basic storage vessel, construction of storage vessels for oxygen, hydrogen, nitrogen, helium, safe devices, drawing of the vessel. • Insulations – Gas filled powder and fibrous, vacuum, evacuated powder and fibrous, multiplayer insulations, mechanism of theral insulation, apparent thermal conductivity, selection of insulation • Cryogenic Fluid Transfer Systems – Different types of transfer lines, process of cryogenic transfer, components of transfer lines. • Application of Cryogenic Systems – Super-conducting bearing, motors, super-conducting magnets, space technology, blood and tissue preservation, cryo probes used in cryo surgery.