Experimental Study in Electrochemical Etchant Using Titanium Alloy for Printed Circuit Heat Exchanger Channels

As a new type of heat exchanger, printed circuit heat exchanger (PCHE) is able to provide heat transfer process with high efficiency under the condition of high temperature and high pressure. The PCHEs made with titanium alloy are required in applications of aerospace, aviation and marine industry due to its lightweight and corrosion resistance. However, available etching technology of titanium alloy is extremely harmful to physical health and environment. An experimental system of electrochemical etchant is developed and the electrochemical etching technology of titanium alloy is studied. During the electrochemical etching process, the effects of electrode voltage, temperature and stirring rate on etching performance are examined. The result shows that electrochemical etching process is able to produce heat transfer channels of PCHE on the order of microns to millimeters. Within the scope of this experiment, the etching rate improves with the etching temperature, and the surface roughness decreases under the lower electrode voltage, as well as the etched surfaces become more uniform with a smaller initial width of the channel. Optimized parameters of producing PCHE heat transfer channels with semicircular cross section is proposed under electrode voltage of 20 V and etching temperature of 45℃.