Numerical analysis of MHD generator with choked flow bifurcation phenomena in subsonic diagonal type MHD generator
- Kyoto Univ., Kyoto-Shi (Japan)
Subsonic flows near sonic condition have strong nonlinearities. For example, a slight variation of boundary condition often causes a transition from a subsonic flow near sonic condition into a transonic flow with choking and shock wave. Since the Lorentz force and the Joule heating can cause a choking of a flow in an MHD channel, a change of load condition can derive a transition into a transonic flow in a subsonic MHD channel. In the paper the choking phenomena in MHD channels are investigated in order to analyze the nonlinear properties of subsonic MHD generators. Choking points are defined as critical points of the flow which is described by the steady state Navier-Stokes equations. The critical point is classified into two kinds by its geometrical property; one of them can appear in the MHD channel, whereas the other cannot appear in the channel and exists at the channel exit. A method of steady state analysis for transonic flow with choking and shock wave considering downstream condition is presented. A steady state analysis of a subsonic diagonal type MHD generator shows that transitions between subsonic flows and transonic flows with choking and shock wave are often accompanied with bifurcation phenomena such as hysteretic behavior of the flow. Hysteretic behavior of the flow with the variation of load condition is shown by a time-dependent calculation in which two stable steady flows, a flow with choking and a flow without choking, exist with the same load.
- OSTI ID:
- 273318
- Report Number(s):
- CONF-930626--
- Country of Publication:
- United States
- Language:
- English
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