关键词: 浸没燃烧式气化器, 跨临界液化天然气, 传热, 数值模拟

Abstract: The thermal resistance of submerged combustion vaporizer(SCV)mainly locates inside the heat transfer tube. The study on the heat transfer characteristic of trans-critical liquefied natural gas (LNG)is of great significance to improve the whole heat transfer efficiency of SCV. Therefore,numerical model was developed to describe the flow and heat transfer process of trans-critical LNG in the tube. The heat transfer law of trans-critical LNG in the tube was analyzed. And the effects of inlet velocity,inlet pressure and heat flux on the heat transfer behaviors were obtained. A new non-dimensional correlation was proposed,which was suitable to predict the heat transfer characteristics of trans-critical LNG. Results showed that the local heat transfer coefficient firstly increases and then decreases,and the maximum value appears in the vicinity of the pseudo-critical temperature. The thermo-physical properties of trans-critical LNG play a vital role in heat transfer enhancement. The local heat transfer coefficient is enhanced with the increase of inlet velocity. The maximum local heat transfer coefficient depends on the inlet pressure within limits. As the heat flux increases,the maximum local heat transfer coefficient appears earlier. The mean absolute percent error of the proposed non-dimensional heat transfer correlation is 6.53%. 99.42% of the data fall within the error zone of ±25%. The study can provide theoretical guidance for the design and economical operation of SCV.

Key words: submerged combustion vaporizer, trans-critical LNG, heat transfer, numerical simulation