A comparison of He with Ar flows for an MHD generator and a closed loop

Abstract

Numerical simulations on the performance of the closed loop for the CCMHD single power generation are conducted, where attentions are paid to the difference of the woking fluids of Ar/Cs and He/Cs. The cycle thermal efficiency depends on the pressure and heat losses. The small pressure loss is preferable to achieve a high enthalpy extraction ratio and to reduce the heat loss in the cooler, which results hi the high thermal efficiency. Since the Ar/Cs loop gives the smaller pressure loss in upstream components of the MHD channel, the thermal efficiency for the Ar/Cs loop is higher than that for the He/Cs loop. The He/Cs loop causes the large pressure loss and insufficient electrical conductivity, which results in the lower enthalpy extraction and thermal efficiency. It is revealed that a loop inlet total pressure is one of the most important operating conditions. The electrical efficiency is improved at the low pressure. The pressure loss due to the wall friction or pebble bed becomes small at the high pressure. The optimal pressure condition is decided by the balance between the pressure loss and the electrical efficiency for each working gas.