热能发生器叶型优化及性能

为了提高热能发生器的水力性能,将热能发生器的工作轮叶片结构由等厚直叶片改造为NACA翼型叶片.运用数值模拟方法对具有不同叶型的叶片在不同转速、不同叶片倾角、不同叶片数下的湍动能耗散率和力矩变化规律进行分析,建立了不同叶片形式、叶片数、叶片倾角的多个数学模型.研究结果表明:NACA翼型叶片在不同转速、不同叶片倾角、不同叶片数下的湍动能耗散率和力矩均大于等厚直叶片,能减轻热能发生器工作腔内液体流动产生的液流角偏离程度;随着转速增大,NACA翼型叶片与等厚直叶片的力矩差值逐渐扩大,液流偏离损失进一步减小,相对弯度较大的NACA6412翼型产生的湍动能耗散率最大,液体流动更剧烈,在3 000 r/min的高转速下产生的力矩比等厚直叶片的大39.2%;当叶片倾角从35°增大到65°时,NACA0012和NACA2412翼型叶片力矩逐渐减小,NACA4412和NACA6412翼型叶片力矩值先增大后减小;不同叶型的工作轮叶片最优叶片数组合不同.

Influence of structural parameters of thermal energy generator on performance

The straight blade with equal thickness was turned into the blade of NACA airfoil to improve the hydraulic performance of the thermal energy generator. The numerical simulation method was used to analyze the variation of the turbulent energy dissipation rate and torque of blades with different profiles when the thermal energy generator at different rotational speeds, blade inclination angles and blade numbers. Several mathematical models of different blade structures, blade numbers and blade inclination angles were established. The results show that the turbulent energy dissipation rate and torque of the thermal energy generator with NACA airfoil blade are greater than that of straight blades with equal thickness at different speeds, blade inclination angles and blade numbers, which can reduce the deviation of the flow angle generated by the liquid flow in the working chamber of the thermal energy generator. With the increase of rotating speed, the torque difference between NACA airfoil and straight blade increases gradually, and the liquid flow deviation loss further decreases. The turbulent energy dissipation rate of NACA6412 airfoil with relative larger curvature is the biggest, and the liquid flow is more intense. The torque value of the thermal energy generator with blade of NACA6412 at the high rotational speed of 3 000 r/min is 39.2% larger than that of the straight blade. When the inclination angles of blade increases from 35° to 65°, the torque value of the thermal energy generator with blade of NACA0012 and NACA2412 airfoils gradually decreases. The torque value of the thermal energy generator with blade of NACA4412 and NACA6412 airfoils first increases and then decreases. The optimal combination of blade numbers is different for different blade profiles.