Characteristics of a Transpiration Cooled Argon ARC

The constrictor wall heat flux characteristics of a high intensity argon arc with a transpiration cooled constrictor are discussed. An apparatus utilizing a segmented plenum chamber is described which provides in contrast to previous experiments more uniform constrictor wall temperatures. This permits lower total transpirant mass flow rates so that laminar flow within the constrictor tube can be maintained. A significant amount of data agrees with the theoretical prediction that the heat flux to the constrictor wall decreases with increasing transpirant mass flux. Data are presented referring to the total energy distribution for the device and the modes of dissipation of heat from the constrictor wall. The effects of turbulence are shown to influence the heat flux to the constrictor, the electric field strength, and the temperature distribution in the arc column.