LNG绕管式换热器管侧流动与传热实验台设计及验证

绕管式换热器是天然气液化的核心设备,然而目前中国天然气液化用大型绕管式换热器的实验研究比较薄弱,相关设计工作的指导理论还不完善.为研究液化天然气(LNG)绕管式换热器管侧流动与传热特性,提出一种可以模拟LNG绕管式换热器实际运行工况的实验方法,并完成实验台的设计、搭建及调试工作.为保证实验数据的准确性,以液相丙烷为实验介质,对其在不同工况下的传热系数进行实测,并将实验所得传热系数与在相同工况下由经典的管内传热关联式计算所得传热系数进行对比.结果表明:实验台可以稳定工作,实验工况可以达到LNG绕管式换热器的实际运行工况,实验测试值与相同工况下的关联式计算值偏差在±10%以内.说明实验台精度较高,实验数据可靠,为LNG绕管式换热器管侧冷凝流动与传热特性的深入研究奠定了实验基础.

Design and verification for tube-side flow and heat transfer test-rig of coil-wound LNG heat exchangers

Coil-wound heat exchangers are the core equipment for liquefaction of natural gas, however, the experimental research on large-scale coil-wound liquefied natural gas (LNG) heat exchangers is relatively weak and the design theory is also imperfect in China. In order to obtain the characters of flow and heat transfer at the tube side of coil-wound LNG heat exchangers, a new experimental method which can simulate the actual coil-wound LNG heat exchangers operation conditions was presented, and then the corresponding test-rig was designed, developed and debugged. For guaranteeing the accuracy of the experimental data, the test-rig was verified by using liquid propane as experiment medium. The tested heat transfer coefficients of propane under different experimental conditions were compared with those from the classic tube heat transfer correlations in the same experimental conditions. It is concluded that the experimental conditions can meet the actual coil-wound LNG heat exchangers operation conditions, and the test-rig can operate stably. The deviation between the tested values and the predicted values is less than ±10%. So the accuracy of the test-rig is high and the experimental data are credible. The test-rig provides an experimental basis for comprehensive research on flow and heat transfer under the actual conditions for large-scale coil-wound heat exchangers.