【作者】 胡汉波；

【导师】 李隆键；

【作者基本信息】 重庆大学 ， 热能工程， 2006， 硕士

【摘要】 当今世界能源短缺的形势日趋严重,而且能源的生产又必然受到经济与环保等因素的制约。直接空冷式凝汽器因为经济、环保、而且具有良好的换热性能,所以在空冷电站系统中得到了越来越广泛的应用。翅片作为构成凝汽器换热面的基本单元,其表面流动传热性能对凝汽器性能起决定性作用。在直接空冷翅片散热器翅片上的传热过程中,翅片的导热和空气的对流换热是相互耦合的,而这在以前的研究中忽略了。本文对直接空冷式凝汽器翅片散热器的三维耦合对流传热过程进行系统的数值模拟,并结合实验研究分析、总结了凝汽器翅片散热器的流动阻力和传热准则关系式,为工程设计提供了科学的依据。另一方面,由于直接空冷电站凝汽器几何结构和流场的复杂性等问题,使得实验研究受到许多限制。而采用CFD软件对其温度场和流场进行数值模拟分析,可以清楚地了解直接空冷凝汽器内部流场的压力、温度、速度等气动热力参数的分布和变化情况,优化其几何结构参数,缩短设计周期。本文研究了不同迎面风速和翅片长度对翅片散热器的传热和流动性能的影响以及不同的横风速度、风机转速、环境温度、风机叶片安装角直接空冷对凝汽器单元空气侧流动性能的影响。研究结果表明:a.采用数值分析对直接空冷凝汽器翅片散热器及进行模拟计算,计算结果与实验结果吻合良好,证明数值分析方法在直接风冷凝汽器翅片散热性能预测上是可行的;b.翅片扁管散热器气侧换热系数和流动阻力都随着迎面风速的增大而增大;在同样迎面风速下,随着翅片长度的增加,翅片扁管散热器的气侧换热系数逐渐减少,流动阻力逐渐增加。通过对模拟数据的回归分析,得出翅片扁管散热器的换热无量纲准则关系式: Nu=3.272354（l/（d_e））^-0.243177·Re^0.346902·Pr^2.370178公式适用范围:40<Re<1800c.横风速度的增大、环境温度的升高,对直接空冷凝汽器单元流场产生不利的影响。散热器出口质量平均速度随着横风速度的增大和在额定转速下,随着环境温度的升高均呈线性减少;风机叶片安装角和风机转速的增大,则对直接空冷凝汽器流场产生有利的影响。散热器出口质量平均速度随着风机叶片安装角和风更多还原

【Abstract】 The world energy short situation is now more and more serious. Moreover, the energy production is influenced inevitably by economy and environmental protection and so on. The direct-cooled condenser obtained the more and more widespread application in the air cooled power plant system because of its economy, the environmental protection and the good heat transfer performance. In the paper, the numerical simulation of the 3-D coupled convective heat transfer in the finned radiator of direct-cooled condenser was performed systematically, the computed results of heat transfer and pressure drop were analyzed with combination of the experimental data, and the corresponding dimensionless criterion relationship of heat transfer was derived, which was provided with the scientific basis for the engineering design.On the other hand, because of the complexity of the geometrical structure and flow structure and so on, the experiment researches on the direct-cooled condenser interior flow field were very difficult. By employing the numerical simulation, the distribution and variation of thermal parameters such as pressure, temperature, velocity and so on in the direct-cooled condenser can be conducted in detail, on the basis of which, we can optimize the geometry structure, shorten the design period. The effect of different front surface wind velocity, the length of fin on the heat transfer and flow performance of single row condenser, and the effect of the different crosswind velocity, the air blower rotational speed, the ambient temperature, the air blower blade angle of setting on the flow performance of direct-cooled condenser unit were studied. The study results showed that:a. Numerical analysis was used to simulate the coupled convective heat transfer of the finned radiator of direct-cooled condenser, the computed results showed well consistency with the experimental result, which proved that the numerical analysis and method is feasible.b. The numerical computations revealed that heat transfer coefficient and the pressure drop to the air side of finned radiator increase with the front surface velocity increase; Under the same front surface velocity, heat transfer coefficient reduces gradually along with the increase of the fin length, and the pressure drop increases gradually. Based on the analog data regression analysis, the dimensionless heat transfer更多还原