Numerical Simulation And Optimization Of A New Open-Frame Vaporizer With Inner Spiral Tubes

LNG (referred to Liquefied Natural Gas) has been widely treated as an efficient andclean energy in the world, and the key equipment in LNG production process is vaporizer,whose research has become an academic hot spot. SuperORV (referred to Super Open-FrameVaporizer) is a type of high efficient heat exchanger, which has many advantages, such ashigh efficiency, large vaporization rate and low running cost. There has been an obvious gapbetween the study of designing vaporizer in China and developed countries. All keyequipments in China have to be imported from abroad. In order to get rid of the awkwardsituation, such as confronting top technology blockade and completely depending on foreigncontractors, it is necessary to fabric a new domestic Open-Frame Vaporizer based on Chinesetechnology.A new Open-Frame Vaporizer with inner spiral tubes has been designed. The researchstarted from inner spiral tube heat transfer mechanism. The results showed: the eddy currenteffect and jet interaction generated by the spiral flow could strengthen the turbulence in fluidas well as thin boundary layer thickness effectively to enhance fluid radial heat transfer ability.Structure and process of the new Open-Frame Vaporizer with inner spiral tubes has beenoptimized, including spiral height, pitch size and material selection.Compared with tranditional tube of SuperORV by numerical simulation method, the newinner spiral tube not only enlarged heat transfer area, but also improved turbulence intensitybecause of rotating effect, which damaging temperature boundary layer to enhance the heattransfer performance. When flow velocity was between0.1and2m/s, Nusset number was1.3~2times higher than that of SuperORV’s tube, and pressure drop were not significant. When5000<Re <20000, heat transfer ability diminished and pressure drop reduced, meanwhile,comprehensive performance first increased and then decreased with the increase of pitch sizeP; heat transfer ability and flow resistance had a U-shape change, moreover, comprehensiveperformance increased when spiral height H became larger; When tubes were respectivelymade of titanium, stainless steel, aluminum and copper, Nuesset number became bigger aslong as Reynolds number raised, and copper tube had maximum Nusselt number, followed byaluminum and stainless steel, and the minimum was titanium.Experiment was carried out on the relationship between heat transfer and flow velocityunder the same numerical simulation conditions. The experimental data was compared withsimulation data. Results showed that the simulation data agreed well with the experiental datawith an average error range of10%, which proved that adopting numerical simulation method has good reliability and convenience.The research not only supplied a theory basis for a new domestic Open-Frame Vaporizer,but also provided an effective support on strong economic improvement and top technologydevelopment in China, which had an outstanding significance.