Heat transfer in thermal plasmas

This review is concerned with some basic studies of plasma heat transfer and with the effects which the results of these studies may have on applications. As typical examples of applications, heat transfer to the walls of a cascaded are and to particulates injected into thermal plasmas will be discussed, including the results of a unified theory for particle heating. As an example of the effects of magnetic fields on plasma heat transfer, some recent results of a r.f. plasma sintering experiment will be reported which revealed unexpected asymmetry of heat transfer to the sintering sample and to the walls of the reactor vessel. The last section of this review will be concerned with experimental and analytical studies of the anode region and with anode heat transfer in high intensity, free-burning arcs which is of interest in the context of are welding and cutting. The results of these studies show that compared to conventional heat transfer, plasma heat transfer is much more complex due to the presence of charged particles, extremely steep gradients and the associated deviations from chemical and/or kinetic equilibrium, and the presence of magnetic fields.