Transient temperature performance of an integrated micro-thermal system

A novel integrated thermal microsystem was designed and fabricated with a h eater microchannels and distributed temperature sensors. This device allows , for the first time, an experimental study of the transient behavior of a thermal microsystem. The transient temperature behavior of the device was s tudied for a variety of heater power levels and forced convection flow rate s, where DI water was used as the working fluid. Both hearing-up rise time and cooling-down fall rime due to a step current input were determined for natural and forced convection heat transfer. The transient temperature resp onse to a sinusoidal power input was also investigated. The resulting tempe rature distribution was measured as a function of the input signal and the how rate. The step response under natural convection is exponential for bot h heating and cooling processes. However, under forced convection, the heat ing-up time response exhibits a clear overshoot. The response time for both heating and cooling process is about four times faster than that for the n atural convection case. Furthermore, under certain conditions, the periodic temperature: response can exhibit a large peak-peak temperature without th e occurrence of dry-out phenomenon.