摘要本实验系统通过将冲击阀、单向阀和空气储能罐组合一体制作成水锤泵,以水锤泵 作为脉动源,以一定落差的水流冲击使水锤泵能够按一定的频率运行,从而产生稳定的 脉动水流。然后使用自行设计的直线型套管式换热器进行冷、热水管路换热,计算一定 量冷水在脉动情况下的换热量,与没有脉动情况下换热量进行比较,从而求得脉动能够 提高的换热性能。95124
同时通过实验测试,对水锤泵的流量、压力变化情况进行研究,发现最大值是原有 压力值的七倍,而最小值为负值,并且变化非常不均匀,也说明水流变化非常复杂,从 而导致压力变化时大时小。但整体上压力都会提升到原有水压值四倍以上,同时压力最 小值会出现负值。同时发现水锤泵的运行需要一定落差的流水冲击,这也就是进水口静 水压,这个静水压最低要超过使冲击阀关闭的压力,如果无法将冲击阀关闭,这个落差 就无法使水锤泵运行。在达到水锤泵所需要的最低落差的同时,还需要一定的水量,确 保流量达到水锤泵所需要的最低流量。
通过进行试验测试,计算得到的相应数据,发现在相同情况下,往复脉动水流换热 量和换热系数都比稳态水流稍微高一点,从而说明脉动水流确实能够提高换热。
毕业论文关键词:水锤泵;脉动流;流动换热;流体压力;套管式换热器
Abstract The experimental system through the impact valve, one-way valve and air tank can be integrated into a water hammer pump, water hammer pump as a pulsating source to a certain drop of water flow so that the water hammer pump can run at a certain frequency, thus Resulting in a stable pulsating flow。 And then use the self-designed linear casing heat exchanger for cold and hot water pipe heat exchange, calculate a certain amount of cold water in the case of pulsating heat transfer, and no pulsation heat exchange rate comparison, Pulsation can improve the heat transfer performance。
At the same time through the experimental test, the water hammer pump flow and pressure changes were studied and found that the maximum value is seven times the original pressure value, and the minimum value is negative, and the change is very uneven, also shows that the water flow is very complex, Resulting in a large change in pressure。 But the overall pressure will be raised to the original water pressure more than four times, while the minimum pressure will be negative。 At the same time found that the operation of the water hammer pump requires a certain drop of water impact, which is the inlet hydrostatic pressure, the minimum pressure to exceed the pressure of the valve to close the pressure, if the impact valve can not be closed, the gap can not make water Hammer pump running。 In order to achieve the minimum drop required for the water hammer pump, it also requires a certain amount of water to ensure that the flow reaches the minimum flow required for the water hammer pump。
Through the test, the corresponding data obtained, found in the same situation, reciprocating pulsating flow and heat exchange coefficient are slightly higher than the steady state flow, so that the pulsating flow can indeed improve the heat transfer。
Key words: water hammer pump; Pulsating flow; flow heat transfer; fluid pressure; tube heat exchanger
目录
第一章 绪论 1
1。1 研究背景 1
1。2 脉动水流换热性能研究现状和发展 1
1。3 水锤泵简介 7
1。3。1 水锤泵 7
1。3。2 水锤泵的工作原理 7
1。3。3 水锤泵的安装条件