螺旋角对航空燃油齿轮泵性能及流量脉动特性的影响

Effects of Helical Angle on Performance and Flow Pulsation Characteristics of Aviation Fuel Gear Pump

关键词:  燃油齿轮泵  重合度  螺旋角  流量脉动  激励力  小波变换

Key words:  Fuel gear pump  Contact ratio  Helix angle  Flow pulsation  Excitation force  Wavelet transform

摘要:

为研究螺旋角对航空燃油齿轮泵性能参数的影响规律，通过坐标变换推导了以圆弧-渐开线-圆弧为端面型线的7齿齿轮泵的型线方程，基于动网格技术和RNG k-ε湍流模型对该泵进行三维瞬态流场数值模拟。通过选定不同的重合度系数，计算比较了4种不同螺旋角齿轮泵的流量特性。研究结果表明：螺旋角对该齿轮泵性能有显著影响，随着螺旋角的增大，齿轮泵出口流量脉动系数呈下降趋势；随着螺旋角依次增大，其他三种角度泵的出口平均流量与螺旋角为23.74°的泵相比分别变化：+1.82%，+2.4%，+0.66%，呈先增后减趋势；经小波变换对齿轮径、轴向受力脉动频率进行分析，其脉动频率与齿轮啮合呈周期性相关；随着螺旋角的增大，齿轮相邻腔室间压力分布逐渐趋于均匀。

Abstract:

In order to study the effects of the helix angle on the performance parameters of the aviation fuel gear pump， the profile equation of the 7-tooth gear pump with circular-involute-circular as the end profile was deduced by coordinate transformation， the three-dimensional transient flow field of the pump is numerically simulated based on the dynamic mesh technique and the RNG k-ε turbulence model. By selecting different contact ratios， the flow characteristics of four different helical angle gear pumps were calculated and compared. The research results show that the helix angle has a significant effect on the performance of the gear pump， with the helix angle gradually increases， the outlet flow pulsation coefficient of the gear pump is decreasing. As the helix angle increases in turn， the average outlet flow of the other three angle pumps changes respectively compared with the pump with a helix angle of 23.74°： +1.82%， +2.4%， +0.66%， showing a trend of first increase and then decrease. The pulsation frequency of gear diameter and axial force is analyzed by wavelet transform， and its pulsation frequency is periodically related to gear meshing. With the increase of the helix angle， the pressure distribution between the adjacent chambers of the gear gradually tends to be uniform.