Heat transfer losses in reciprocating compressors with valve actuation for energy storage applications
Heat transfer losses in reciprocating compressors with valve actuation for energy storage applications
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DOI：
10.1016/j.est.2017.07.024
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发表时间：
2017-12
影响因子：
9.4
通讯作者：
C. Willich;Alexander J. White
中科院分区：
文献类型：
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作者：
C. Willich;Alexander J. White
了解压缩机和膨胀机中传热引起的火用损失对于许多储能应用（如压缩空气和泵送储热）非常重要。为了更好地了解这些损失，对简单的气体弹簧、具有内部网格以模拟阀流的气体弹簧以及具有功能性入口和出口阀的往复式压缩机进行了CFD模拟。对这三种情况下的壁面热交换进行了研究和比较。所采用的模型以前已经验证了一个简单的气体弹簧使用文献中的实验数据。对于具有内部网格的气体弹簧，发现增加的混合导致更高的热传递引起的滞后损失，并且（在高活塞速度下）导致显著的压力损失。这两种类型的损失可以通过绝热壁计算来区分。对于压缩机（即，对于阀流），循环中的热传递在很大程度上取决于阀定时。例如，在1500 rpm下，当输送阀在7 bar下打开时，压缩的初始阶段的热传递系数与简单气体弹簧的热传递系数相似，而对于6 bar下的相同速度，热传递系数增加一倍以上。
Understanding the exergy losses stemming from heat transfer in compressors and expanders is important for many energy storage applications such as compressed air and pumped thermal storage. In order to obtain a better understanding of these losses, CFD simulations were performed for simple gas springs, for a gas spring with an internal grid to mimic valve flow, and for a reciprocating compressor with functioning inlet and outlet valves. The wall heat exchanges for these three cases were examined and compared. The model adopted has previously been validated for a simple gas spring using experimental data from literature. For the gas spring with an internal grid it was found that increased mixing leads to higher heat-transfer-induced hysteresis losses and (at high piston speeds) to a significant pressure loss. These two types of loss can be distinguished by undertaking adiabatic-wall calculations. For a compressor (i.e., with valve flows) heat transfer over the cycle depends very much on valve timing. For example, at 1500 rpm, when the delivery valve is opened at 7 bar the heat transfer coefficient for the initial stages of compression is similar to that for a simple gas spring, whereas for the same speed at 6 bar it is more than doubled.