In [1], the correct quasi-one-dimensional (Q1D) electrodynamical part (the electric current density vector in a working fluid has only one component: jy) of a model for the fluid flow in a Faraday ideally segmented (absence of the Hall electric current: Ix = 0) generator channel was developed. In this paper, the validity of the model is demonstrated for the electric currents of interest for commercial MHD energy conversion with combustion products as a working fluid [3], and the semi-empirical factor †x from the model is further investigated.
It seems that in modeling in electrodynamics or electromagnetics the consequences of taking an assumption, better say a simplification, are the same as in fluid dynamics. By simplifying a problem we cut some of the connections of a model with reality, i.e. we partially destroy some of the equations and then they can be only partially satisfied. The most safe way to find, then, the connections left is to try to satisfy all the equations which can still be satisfied in the frame of the assumption(s) taken. In question are the models of fluid flow in a Faraday ideally segmented channel, which have the Q1D electrodynamical part as defined above, or based on the assumption that the x component (besides jz = 0, Ez = 0) of the Faraday current jx does not exist in the core of the flow, e.g. [3–6]. The assumption that the electric current flows inside a channel through the whole cross section of a segment (s2b), even in the core of the flow, does not correspond to reality [14]. It leads to an underestimation of the working fluid electrical resistance. One has to admit that in the frame of the assumption jx = 0 it is impossible to describe the reality inside a channel. But, it is still possible to describe the global characteristics of a generator: electrical output, electrical and thermal efficiency, etc. with the Q1D model legitimate regarding the equation of conservation of charges (div j = 0 for the stationary electric current) [1]. 相似文献
