Abstract
Optimized design conditions of pebble bed regenerative heat exchangers are discussed from the standpoint of minimizing their pressure loss with a minimum reduction in thermal performance. Blow-down experiments for heating argon by hot air or by combustion gas were carried out to measure the pressure loss of argon in a pebble bed. Suitable equations for predicting the pressure loss were selected based on the measured results. The optimum values of pebble diameter and the mass flow rate of a working gas were determined by calculating pressure loss and thermal performance of pebble bed regenerative heat exchangers under cyclic continuous operation. The use of helium as a working gas in closed cycle MHD, instead of argon, proved to be advantageous from the viewpoint of both pressure loss and thermal performance.
