Comparative study of the transient natural convection in an underground water pit thermal storage
Comparative study of the transient natural convection in an underground water pit thermal storage
复制标题
地下水坑蓄热场瞬态自然对流对比研究
DOI：
10.1016/j.apenergy.2017.09.036
复制
发表时间：
2017-09
期刊：
影响因子：
11.2
通讯作者：
Ding Yulong
中科院分区：
文献类型：
--
作者：
Chang Chun;Wu Zhiyong;Navarro Helena;Li Chuan;Leng Guanghui;Li Xiaoxia;Yang Ming;Wang Zhifeng;Ding Yulong
研究了地下水坑储热库中热损失通过周围墙壁的瞬时自然对流现象。建立了实验台，建立了数值模型，得到了水池蓄热器的温度分层特性。假设流体性质是恒定的，除了密度随温度的变化，这是使用Boussinesq近似处理。实验结果表明，温度场的模拟是合理的，最大相对误差为± 9.77%。结果表明，由于热损失的影响，壁面附近的水温降低，导致沿倾斜侧壁沿着流动。一个轻微的向上流动发生在水坑热存储的中心，这将提高温暖的水到一个更高的水平。结果，浮力驱动的流动逐渐建立在水池蓄热器中的热分层。模拟结果还表明，倾斜侧壁内表面和罐底的平均努塞尔数远高于顶部隔热层的平均努塞尔数。由于强烈的换热，蓄能效率在前5 min内迅速下降，从100%下降到83.19%，然后在40 min后趋于平稳。自然对流的最大速度出现在倾斜侧壁的上部附近，并随着冷却过程的发展而减小。本文的工作填补了现有研究的差距，对水坑蓄热的设计具有一定的指导意义。
This study investigated the transient natural convection phenomenon in an underground water pit thermal storage with heat losses through the surrounding walls. An experimental test rig was built up, and a numerical model was developed to obtain the characteristics of the thermal stratification in the water pit thermal storage. Fluid properties are assumed to be constant, except for the density changes with temperature which is treated using the Boussinesq approximation. The simulations of temperature profiles are reasonably proved by experiments with the maximum relative errors of +/- 9.77%. The results show that water temperature decreases close to the walls due to the heat losses, which leads to a downward flow along the inclined sidewalls. A slight upward flow occurs at the center of the water pit thermal storage, which lifts the warmer water to a higher level. As a result, the buoyancy-driven flow gradually builds up the thermal stratification in the water pit thermal storage. The modelling results also show that the values of the average Nusselt numbers on the inner surface of the inclined sidewalls and the bottom of the tank are much higher than that of the top thermal insulation layer. The thermal energy storage efficiency decreases rapidly in the first five minutes from 100% to 83.19% due to the intense heat transfer, and then tends to level off at the end of 40 min. The maximum velocity of the natural convection appears close to the upper part of the inclined sidewalls, and it decreases with the cooling process evolved. The present work has a valuable attempt to fill the gap in the existing studies and is useful for guiding the water pit thermal storage design.
登录
查看更多内容
影响因子：
8.7
作者：
Zhengou Yang;Haisheng Chen;Liang Wang;Yong Sheng;Wang Yifei
通讯作者：
Zhengou Yang;Haisheng Chen;Liang Wang;Yong Sheng;Wang Yifei
影响因子：
8.7
作者：
A. Uçar;M. Inalli
通讯作者：
A. Uçar;M. Inalli
影响因子：
11.2
作者：
María Ibáñez-Puy;Javier Bermejo-Busto;C. Martín-Gómez;M. Vidaurre-Arbizu;J. A. Sacristán-Fernández
通讯作者：
María Ibáñez-Puy;Javier Bermejo-Busto;C. Martín-Gómez;M. Vidaurre-Arbizu;J. A. Sacristán-Fernández
影响因子：
11.2
作者：
Navdeep Pandey;K. Murugesan;H. Thomas
通讯作者：
Navdeep Pandey;K. Murugesan;H. Thomas
DOI：
10.1016/j.ijheatmasstransfer.2012.10.038
发表时间：
2013-01
影响因子：
5.2
作者：
R. Oliveski
通讯作者：
R. Oliveski