Development of an Energy-Efficient and Highly Sensitive Thermal Microsensor for Measuring Flow Rates of Fluids

A calorimetric-based thermal sensor is precisely designed to measure volumetric flow rates in water, air, and nitrogen. Extensive simulations of the sensor's performance are conducted using COMSOL Multi-physics® software. In order to validate the simulation results, a comprehensive comparative analysis is carried out, utilizing the well-established one-dimensional model proposed by Nguyen and Dötzel, The sensor's construction incorporates high-quality materials such as titanium, phosphorus-doped amorphous hydrogenated silicon carbide (P-doped a-SiC:H), aluminum, and borosilicate glass substrates, ensuring robustness and reliability. The measurement range investigated spans from the flow rates of $0\ \mu\mathrm{l}/\text{min}$ to $45\ \mu\mathrm{l}/\text{min}$ for water, while for air and nitrogen, a broader range of 0 ml/min to 187 ml/min is considered. The evaluation of results showcases a low power consumption of approximately 7.6 mW, underlining the sensor's energy efficiency. Furthermore, the sensor exhibits remarkable sensitivities, with values reaching 54.89 mV/(mm/s)/mW for water flow and 8.9 mV/(m/s)/mW for gases, underscoring its exceptional performance across various applications.