Repurposing A Vehicle Mass Flow Sensor for Measuring Air Flow Rate on A Solar-Dish Brayton Cycle
摘要
The performance of the micro gas turbine in a solardish Brayton cycle depends on several factors of its upstream and downstream components. These include pressure and temperature. Its fundamental operation is dependent on combustion making it a hybrid. In controlling emissions from the internal combustion engine process, the automobile industry has over the years fully developed mass air flow (MAF) sensors to be accurate and ensure optimum and environmentally-friendly engine performance. Its development has reduced its cost. The sensor plays an integral role in keeping emissions from internal combustion engines within acceptable margins by providing information required to control fuel consumption. The University of Pretoria’s Solar Thermal Spoke is developing a solar-dish Brayton cycle integrated with concentrated solar power for electricity and heat generation. This cycle is sensitive to pressure drop in both upstream and downstream components, and its flow rate must be accurately monitored and controlled to ensure the optimal steady-state turbine operation. In this work, the Bosch HFM5 hot film MAF sensor is repurposed from the vehicle industry application for incorporation in the solar-dish Brayton cycle. The inclusion of the MAF sensor reduces the costs and improves performance. This paper presents the results of in-lab calibration of the low-cost vehicle MAF sensor against a high-cost, high-accuracy industrial flow meter, the SUTO S421 thermal mass flow sensor. The MAF sensor showed accuracy of 95% in the lower range flow rates of 0 to 75 kg/h and higher flow rate of 250 to 360 kg/h. The mid-range 75 to 250 kg/h range showed less accuracy of up to 85%.