LNG微通道气化器四段设计方法及数值模拟

Four-segmented design method and numerical simulation of LNG micro-channel vaporizer

微通道气化器具有换热效率高、耐高压、结构紧凑等优点,作为LNG气化器具有广阔的应用前景。目前,LNG微通道气化器大多采用分段法设计,但该方法需编程计算,且计算量大,不利于在工程中推广应用,因此,提出了一种微通道气化器四段设计方法。根据换热工质各状态的温度分界点将气化器分为4段,通过热平衡计算、结构设计计算获得各段传热量、传热面积及压降,从而计算得到总换热面积,计算结果与文献分段法设计结果相差13.4%。采用数值模拟方法对设计的微通道单元进行流动传热特性模拟,通道温度和压降模拟值与四段法计算值吻合较好,验证了LNG微通道气化器四段设计方法的可靠性。该方法分段合理、计算量小、结果直观可靠,为LNG微通道气化器设计和优化提供了有效途径。

Micro-channel vaporizer has the advantages of high heat exchange efficiency,high pressure resistance and compact structure,and has broad application prospect as an LNG vaporizer.Presently,most of the LNG micro-channel vaporizers are designed by the segmentation method,which requires massive calculation by the programming computation,and it is not conductive for its promotion and application in engineering.Therefore,a four-segmented design method was proposed for the LNG micro-channel vaporizer.The vaporizer is divided into 4 segments based on the temperature of working fluids under different phases.Then,the heat transfer amount,heat transfer area and pressure drop of each segment can be obtained through the heat balance calculation and structural design calculation,and thereby the total heat transfer area can be calculated.The calculation results have an error of 13.4%compared with that given in the reference.The numerical simulation for the flow and heat transfer characteristics of the designed micro-channel unit shows that the simulated values of the channel temperature and the pressure drop are well consistent with the calculated values of the four-segmented method,and thereby,the reliability of the four-segmented design method for the LNG micro-channel vaporizer is verified.Generally,the method has the characteristics of reasonable segmentation,less calculation,and intuitive and reliable results,which provides an effective way for the design and optimization of LNG micro-channel vaporizer.