Seminario Dr. Mehdi Souli - IPN/IN2P3/CNRS Orsay
Design and test of a cryogenic heat exchanger for a high power CW power coupler for superconducting radiofrequency proton cavities
Sep 21, 2007
from 03:00 PM to 04:00 PM
|Where||LASA - Sala Seminari|
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The Eurotrans accelerator program, funded by EURATOM in the 6FP of the EC, is devoted to the design of a superconducting linac as a driver for a nuclear waste trasmutation system. The coaxial power coupler needed for the superconducting RF cavities should transmit up to 150kW of RF power to the proton beam in CW operation. The inner conductor is water-cooled to remove 256 W heat load in standing wave mode operation and to limit the thermal radiation to the cavity beam pipe. A full-scale copper coil tube cold heat exchanger brazed around the outer conductor and using supercritical helium as coolant was designed and tested at Orsay. This cooling circuit was optimized for removing 92 W heat flux simulating RF losses in standing wave mode operation, while minimizing the heat load to the cold extremity maintained at 2 K or 4.2 K, with minimum pressure drop and maximum heat transfer coefficient. A dedicated test facility named SUPERCRYLOOP was developed and successfully operated for measuring the performance of the cold heat exchanger and investigating the thermohydraulic behaviour of supercritical helium as function of different parameters (inlet pressure, flow rate, heat load…). The test cell used reproduces the realistic thermal boundary conditions of the power coupler mounted on the cavity in the prototype cryomodule under joint development by IPN and INFN for the Eurotrans program. After description of the test apparatus, the experimental data will be presented and discussed then compared to numerical simulation results to validate the design.