Study On The Structure Optimization Of The Average Wind Speed Sensor

The accurate measurement of air supply system of central air-conditioning is one of an important prerequisite for energy-saving control of air-conditioning system. In order to improve the accuracy of wind speed measurement in the pipe of air conditioning system, this paper has designed a new average wind speed sensor by optimizing the cross-section shape of the sensor. It is to solve the problem of not high accuracy, low output pressure difference and instable flow coefficient about low wind speed measurement in pipelines of air conditioning systems. The specific work of this paper mainly include:Firstly, we established the geometry model of the slice 2D CFD simulation of the average wind speed, air volume sensor. The model is used to improve air velocity and volume sensor, which is applied to the existing central air conditioning pipe about low wind speed measurement. In the gambit software, we drew flow field calculation, meshed blocked grid and set the boundary conditions of the model.Secondly, we obtained optimal two-dimensional simulation parameters, which is suitable for low wind velocity measurement in central air conditioning pipe. Through the comparative analysis of laminar, standard k-ε model and SST k-ω model, and the set conditions in the simulation, which influence the flow coefficient, the optimum parameters were obtained. They were applied to low wind speed measurement for the two-dimensional simulation of central air conditioning pipe.Thirdly, simulation study the validity of the simulation model for air conditioning system with the flow rate in 3m/s-30m/s scope. According to the best simulation setting conditions, the simulation results of measuring coefficient in 6% error range, consistent with the actual measuring film coefficient.Finally, we designed the optimal geometrical dimensions of detecting rod section of average wind speed measurement sensor, which is applied in air conditioning pipe about low wind speed measurement. By using FLUENT software, two-dimensional simulation experiments were done to explore how the geometrical dimensions influence the performance of the average wind speed sensor. These geometrical dimensions are the semicircle radius which is at the front of detecting rod section and the length of intermediate level section. When the semicircular radius in the front end of cross section is 6.5mm and the length of intermediate cross section is 9.75 mm, it can effectively increase the output pressure of average wind speed sensor and improve the measurement accuracy.We can draw the conclusions from research results. Firstly, standard k-ε model is more appropriate for air conditioning system in low speed applications. Secondly, with cross section radius increased, the overall trend of flow coefficient first becomes decreased and then increased. It can reduce the flow coefficient, but the cross section radius can not be increased indefinitely. Thirdly, with the length of the horizontal cross section increased or decreased, within the range of 1.25 mm, it can not effectively improve the performance of average wind speed sensor. The study for the design of a suitable geometrical dimensions of detecting rod section of average wind speed measurement sensor, which is used for central air conditioning pipe about low wind speed measurement, has a certain reference significance.