Improvement of enthalpy extraction over 30% using a disk MHD generator with inlet swirl

Abstract

Performance of a disk-type CCMHD generator has been investigated. In the present power generation experiments, special attention has been devoted to the effect of inlet swirl on generator performance. In order to clarify this effect, one-dimensional numerical simulation has also been performed. The results showed that the enthalpy extraction ratio was successfully improved up to 32.5% by employing inlet swirl with the swirl ratio S(= U 0 U r ) of 1. Static pressure and Hall potential distributions were measured and showed that the inlet swirl reduced the steep increase in static pressure owing to the strong Lorentz force at the inlet of the disk channel. Hence, relatively low static pressure and, thus, high Hall parameter were kept throughout the channel, and therefore, the remarkable increase in output performance was achieved. Numerical simulation can qualitatively confirm these experimental results well. Realization of high Hall parameter and high enthalpy extraction with smaller pressure ratio of inlet to exit for the case with inlet swirl led to improvement of the isentropic efficiency.