印刷电路板式LNG气化器热工水力性能数值模拟与优化OA

Printed circuit heat exchangers(PCHEs),as highly efficient microchannel heat exchangers,offer significant advantages such as compact structure,high efficiency,and reliable safety,which has promising application prospects.But the wave-channel PCHE has been rarely studied.In this study,orthogonal numerical experimental design was employed to optimize the thermal-hydraulic performance of a wave-channel printed circuit vaporizer(PCV)for LNG.Amplitude,wavelength,and cold/hot channel cross-sectional shape were selected as experimental factors,each with three levels.The comprehensive evaluation factor G served as the optimization criterion.The following results are obtained.First,PCV with an amplitude of 3 mm,a wavelength of 25 mm,a semicircular cross-sectional hot channel,and a circular cross-sectional cold channel exhibits the best overall performance.Second,the wave-channel PCV induces periodic disturbances on the internal fluid due to its cyclically varying channel geometry,causing the acceleration core to move periodically.This thins or even disrupts the boundary layer,thereby enhancing heat transfer efficiency.Third,changes in the thermal properties of the fluid generate buoyancy forces within the flow channel,inducing secondary flows that form vortices.The wave-shaped channel induces periodic migration of vortices,which can enhance fluid mixing,thereby intensifying convective heat transfer.Fourth,the orthogonal numerical experimental approach can effectively identify remarkable performance-influencing factors in multiple geometrical parameters,thus allowing for efficient optimization.In conclusion,the proposed optimization model and resulting optimal structural parameters offer direct references for the design of efficient and compact LNG vaporizers,and also provide valuable insights for the structural optimization and performance improvement of equivalent microchannel heat exchangers.