TRANSIENT AND STEADY-STATE THERMAL DESIGN EVALUATION OF A CARBON-MONOXIDE GAS SENSOR USING CFD TOOL

This paper summaries thermal modeling work performed on the Motorola C arbon Monoxide (CO) chemical sensor. Gas sensors need low cost reliabl e packages, good thermal operation, and low power consumption. The goa l is to provide a validated thermal model of a gas sensor and its pack age and to develop a sensor design capability with reduced design cycl e time. Due to the complex structure of the sensor package, a computat ional fluid dynamics (CFD) tool was used to analyze the heat transfer and fluid flow within the package. Based on the validated model parame tric studies on filter location and package orientation were performed . In order to minimize the influence of humidity, the sensor is toggle d between high and low temperatures by applying 5 volts for 5 s of hea ting, and 1 volt for 10 s of cooling. Transient thermal analysis was a lso performed to predict the temperature response of various component s. A detailed description of the thermal model and its results are des cribed in the paper.