SIMULATION OF HEAT TRANSFER CHARACTERISTICS BETWEEN AIRFLOW AND ELECTRODES IN HYPERSONIC MAGNETOHYDRODYNAMIC GENERATOR
In this research effort, numerical simulation of three dimensional magnetohydrodynamic (MHD) generator with segmented Faraday electrodes is performed and the convective heat transfer characteristics between hypersonic airflow and electrodes is studied. The numerical procedure adopts five-equation model which includes the full Navier-Stokes equations supplemented with electromagnetic source terms and Poisson equation for consistency of the electric field with current continuity. Results show that a large number of electric energy coming from the mainstream area converts into Joule heat at the boundary regime near the electrode where the value of Joule heat power is about an order of magnitude larger than that in the center. The Joule heat effect produced by electromagnetic field makes the temperature field distributed differently. The load coefficient can effectively control the thermal boundary layer thickness and the magnetic field intensity can control the ratio of power converting into Joule heat near the electrode, thereby controlling the heat transfer characteristics between the airflow and the electrode. With the increase of load coefficient or the decrease of magnetic field intensity, Joule heating effect increases obviously near the electrode and Joule heating becomes the leading role of heating electrodes instead of viscous heating gradually. The heat transfer intensity between the airflow and the electrode is the strongest at the junction of the electrode and the insulating wall.