Research On Hydrogen Consumption Of Fuel Cell Veichle Based On Flow Measurement Method

As fuel cell vehicle has become the ideal scheme to solve the problem of global pollution and energy shortage, the accurate measurement of hydrogen consumption becomes an urgent need. At present, there are three hydrogen consumption measurement methods in the world, which are weight, temperature pressure and flow method. Compared with the other two methods, flow method is an easy way to measure hydrogen consumption of fuel cell vehicles in real-time. Therefore, flow method has more practical value and significance to study, but the existing studies have shown that flow method is low in accuracy.First of all, the measurement deviation of flow method was analyzed by ANSYS-CFD simulation. At present, most of the mass flowmeters used for fuel cell vehicles are calibrated primarily by water. As this research called for high flow measurement accuracy of±1%of Reading (RD), calibrating the mass flowmeter by sonic nozzles directly with hydrogen can eliminate the measurement error. Then the computer measurement and control system of sonic nozzle hydrogen flowmeter calibration device was developed. The hardware integration was completed and the software was developed based on Labview.The critical factors and the representative equations for hydrogen were analyzed. The reduced Helmholtz free energy of state for normal hydrogen was used as thermophysical equation, and the nonlinear binary Newton iteration method was used to calculate the isentropic exponent of the nozzle throat for hydrogen. The uncertainty of the device was analyzed and tested by the weight method device. The flow stability was analyzed and the flow stability test was carried out. Then the calibration method based on piecewise linear interpolation was designed.After the preparation before hydrogen test, a coriolis mass flowmeter and a thermal mass flowmeter were calibrated by the sonic nozzle device with hydrogen according to the specific test process. In addition, a thermal controller was used to simulate the actual working condition to verify the measurement accuracy under transient flow condition. The accuracy of the calibrated mass flowmeters remained stable within the limits of±1%RD.