Development of A Test Facility and Measurement of Performance of A Three Stream (He/He/He) Plate Fin Heat Exchanger

Abstract

The Helium refrigeration/ liquefier plant (HLP) being developed at Institute for Plasma Research, needs many high efficiency plate-fin heat exchangers(PFTE) to cool compressed helium gas down to ~5 K. Among these, the 5thheat exchanger which cools helium gas from ~27 K to ~15 K is a 3-stream counter flow (He/He/He) plate fin Heat exchanger (PFHE). For this purpose, vacuum brazed aluminium plate fin heat exchanger was designed at IPR. Aproto type of this has been manufactured by an Indian manufacturer. With an objective to measure the heat exchanger performance, a closed loop cryogenic test facility with piping, valves, temperature, fixture, interconnections, layout of room temperature and cryogenic components with proper support. Essential insulation has to be designed to minimize the parasitic heat load to the cryogenic components, which can lead to significance error in measurement of performance. This prototype will be tested for its thermo hydraulic performance between the temperature ranges of 300 K to 80 K. This prototype heat exchanger will be installed along with another LN2-cooled plate fin heat exchanger which is expected to bring the temperature of warm high pressure Helium gas from ~100 K (outlet from three stream HE) to ~80 K by the use of LN2. This cold Helium gas at the outlet from this LN2heat exchanger will attain about 80 K. A heater can be used to bring it up to 120 K before going to 3-stream heat exchanger whose performance will be measured. It is slated that, the pressurised Helium gas will be circulated with help of a blower in unavailability of any Helium compressor and oil removal system. Pressure drops through the heat exchanger will be measured for different operating pressure and Helium flow rates, and that will be verified by the software at IPR. Likewise the thermal effectiveness and equivalent heat transfer coefficient will be calculated from the measured temperatures of stream. This will be further verified using the software.