Studies on a high temperature regenerative heat exchanger for closed cycle MHD power generation, 1

A packed pebble bed regenerative heat exchanger for heating argon by natural gas fired combustion gas was installed and tested. The maximum temperature at the top of the pebble bed was 18500C and that of argon at the exit of the heat exchanger was 16500C. The molecular impurity level contained in the heated argon was less than 100 ppm. These results show that the performance of the heat exchanger is satisfactory. One dimensional heat transfer analysis in the pebble bed showed that the changes of temperature distribution in the bed during the heating and the argon blowing periods can be predicted using the known heat transfer coefficients between gas and pebble. (author)