Ventilation And Air Conditioning Duct Air Dampers Groove Resistance Reduction And Resistance Prediction

In order to reduce the energy consumption of ventilation and air conditioning systems and help China’s construction industry achieve "carbon peak" and "carbon neutral",this paper takes the common single-leaf damper in ventilation and air conditioning ductwork as the research object,analyzes the velocity field and pressure field distribution in the duct of the dampers.Based on the bionics,we propose the optimization of the traditional smooth damper plate to the damper plate with micro trapezoidal groove surface,and analyze the effect of different damper opening,different groove size,different groove arrangement and different inlet wind speed on the resistance reduction rate of the damper.Using a combination of numerical simulation and experiment,the velocity field and pressure field of the conventional dampers at different wind speeds in fully open condition are tested by full-scale experiment;the local resistance coefficients and resistance reduction rates of the conventional dampers and optimized dampers of different configurations under different working conditions are compared by numerical simulation,and their resistance characteristics are analyzed,and the recommended structural form,size and arrangement of the resistance reduction grooves are obtained.Finally,the resistance prediction of dampers with different opening degrees and different groove sizes is achieved by applying gray model and genetic algorithm optimized neural network model.The specific research results are as follows:(1)By adding micro trapezoidal grooves of suitable size at the damper plate,it can reduce fluid deformation and vortex strength,play a role in stabilizing the airflow organization,and achieve the purpose of reducing resistance and consumption.(2)The resistance characteristics and drag reduction effect of dampers with different dampers opening,groove size,horizontal and vertical arrangement were studied.The results show that the resistance reduction rate of the new dampers tends to be stable when the opening is less than 40° and more than 70°,and the resistance reduction rate is inversely proportional to the opening of the dampers between 40° and 70°;the groove configuration with the best resistance reduction effect is the transverse micro trapezoidal groove with S1=6 mm,S2=1.5 mm,d=1 mm and h=2 mm,and its resistance reduction rate is up to 7.71%.(3)The multidimensional gray model GM(1,N)and genetic algorithm optimized neural network model GAGM prediction system was applied to achieve the prediction of the resistance change due to the change of the structural parameters of the dampers.The results show that the maximum error of the GM(1,N)model prediction curve is 23.01%and the average error is 11.05%when compared with the CFD numerical calculation results;the maximum error of the genetic algorithm optimized neural network model GAGM model is 9.42%and the average error is only 4.65%,the prediction results achieved a good agreement with the CFD numerical simulation results.