Ds Nadig

DEVELOPMENT OF CRYOGENIC LOOP HEAT PIPE

The design of a cryogenic loop heat pipe (CLHP) is presented in the paper. As the wick is required only in the evaporator section, very small pore size wicks can be used in applications with high thermal transport requirements and/or where the heat must be transported over a long distance against gravity. A FORTRAN program to solve the mathematical model and to determine the parameters for various boundary conditions has been developed. The CLHP is designed to transfer 5W heat at 70K using nitrogen or oxygen as working fluid. It will be a self priming type device which can operate against gravity with evaporator above the condenser as well as under microgravity condition. A G-M type single stage double inlet pulse tube refrigerator is coupled to the CLHP to test its performance. The mathematical model, design, fabrication integration of the heat pipe with the pulse tube system and testing with stainless steel wick at the evaporator will be described in the paper.

Experimental Studies of Convection in a Single Stage Pulse Tube Refrigerator

A single stage Pulse Tube Refrigerator has been designed, fabricated and operated with a 3kW GM type helium compressor with an indigenously developed rotary valve in the frequency range from 1.2 to 2.3Hz. The system produces a lowest temperature of 37.5K and a refrigeration power of 7.3W at 77K. The cold end temperature Tc of the Pulse Tube refrigerator depends on its orientation angle

Design, development and calibration of HTS wire based LOX level sensor probe

\theta

Performances of single and two-stage pulse tube cryocoolers under different vacuum levels with and without thermal radiation shields

with respect to gravity vector and the increase in Tc arises due to the convection in the Pulse Tube. The lowest temperature occurs at

PALLADIUM DOPED TIN OXIDE BASED HYDROGEN GAS SENSORS FOR SAFETY APPLICATIONS

\theta = 0°

Calibration and linearity verification of capacitance type cryo level indicators using cryogenically multiplexed diode array

. The increase in Tc with change in

Studies on a Single Stage GM type Pulse Tube Cryocooler Using an Indigenous Helium Compressor

\theta

Development and test of a cryopulverizer for reprocessing plastic wastes

is small till about 70°. However, beyond this angle, Tc varies strongly and reaches a maximum value at

Development of a reliable and simple pressure wave generator for pulse tube refrigerators

\theta ~ 120°

Studies of cryotreatment on the performance of integral diaphragm pressure transducers for space application

and decreases thereafter upto 180°.For a better understanding of convection phenomenon, detailed experimental studies have been performed on two pulse tubes with the same i.d. 13.3mm, but with lengths 250 and 300mm. The orientation dependence of Tc and the cooling power characteristics have been studied at different frequencies (1.2 Hz to 2.3 Hz) at two different pressures. The results have been analysed to obtain the experimentally observed heat flux due to convection,