Abstract Accurate airflow measurement is the key to realize the thermal comfort and energy saving management of VAV air conditioning system, especially for that under low air flowrate conditions. This paper proposed a novel damper torque airflow sensor to solve the problem of low range airflow measurement of VAV terminals. The flowrate model is established based on resistance characteristic analysis and the flow coefficient is studied by CFD simulations and experiments. The simulation and experiment results show that there is a good negative linear relationship between the flow coefficient K ( θ ) and damper opening angle in the range of 10°–50° and the decreasing trend of K ( θ ) is more intense and nonlinear in the range above 50°. Under the general damper opening range (10°–70°), the quadratic fitting equation of K ( θ ) can basically meet the error requirements ±5%, but the error is larger as the opening angle exceeds 70°. As the damper opening increases, the airflow rate increases and the torque changes in a very small range under constant static pressure inlet condition, and the proposed airflow sensor has high measurement range ratio of more than 25:1. The study in this paper is helpful to promote the energy saving and building comfort of VAV system.

中文翻译：

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基于电阻特性分析的新型VAV终端风门扭矩气流传感器研究

摘要 准确的气流测量是实现变风量空调系统热舒适和节能管理的关键，尤其是在低风量条件下。针对VAV终端低量程气流测量问题，提出了一种新型风门扭矩气流传感器。基于阻力特性分析建立了流量模型，通过CFD模拟和实验研究了流量系数。仿真和实验结果表明，流量系数 K ( θ ) 与阻尼器开度在 10°～50° 范围内呈良好的负线性关系，且 K ( θ ) 的下降趋势更为强烈且非线性。 50°以上的范围。在一般风门开启范围（10°-70°）下，K(θ)的二次拟合方程基本可以满足±5%的误差要求，但开度超过70°时误差更大。随着风门开度的增加，在恒定静压入口条件下，风量增加，扭矩在很小的范围内变化，所提出的气流传感器具有超过25：1的高测量量程比。本文的研究有助于促进VAV系统的节能和建筑舒适性。