Comparison of different large size linear MHD generator systems

In this paper an MHD generator obtained by two separate channels (G1, G2) is considered. The outlet section of the first channel is connected with the inlet section of the second one by a transition region (D). Each channel has its own saddle shaped magnet. A distribution of the magnetic field on the axis of the channels with different peak values can be produced, and different gas flow conditions for the two channels can be established. The performance of the two channels system is compared with that of a single channel (G0) with a single saddle shaped magnet. A quasi-one-dimensional code (MHD1D) is utilised for the channel design and an integral code (SADDLE) is utilised for the saddle shaped magnet design. Both the MHD1D and the SADDLE codes are based on a design optimization procedure. The design problem of the MHD channel and of the saddle shaped magnet are formulated as non linear, constrained optimization problems which are solved by means of a sequential quadratic programming algorithm. Different solutions for the two channels system are studied. For each solution the mass flow rate through the two channels generator is equal to that of the generator G0. Firstly by means ofmore » the codes NMD1D and SADDLE, the design of G1 is performed. By these calculations the stagnation parameters at the inlet section of generator G2 are known, and the design of G2 is done. The generator parameters (electrical power output, compression power, heat losses) and the magnet parameters (superconductor volume, stored energy) are compared with those of the generator G0. A parametric analysis is done in order to find the best configuration for channels G1 and G2. A discussion of the results is presented.« less