Inthefirstpartofthiswork(PartI),wepresentedandvalidatedtheDSMC-HFSmethod,whichcanbeusedtodealwithheatfluxspecifiedboundaryconditionsinDSMCsimula-tions.Inthisarticle,themethodisappliedtodemonstratethegeneralpropertiesofrarefieddiatomicgaseousflowinamicrochannelunderuniformheatfluxboundaryconditions.Theeffectsofwallheatfluxongaseousflowandheattransfercharacteristicsareinvestigatednumericallyanddiscussedindetail.Itcanbeconcludedfromthepresentresearchthatgaseousrareficationandcompressibilityincreasewiththeincreaseofthewallheatflux.Gasaccelerationathigherwallheatfluxismoreobviousthanthatatlowerwallheatflux.Thehighwallheatfluxreducesthemassflowrateandelevatestheheattransferabilityexceptatthechannelinlet.

Forflowsassociatedwithmicroelectromechanicalsystems(MEMS),theheatfluxspeci-fied(HFS)boundaryconditionexistsbroadly.However,problemswiththeHFSboundaryconditionhavenotbeenwellrealizedinthesimulationsofmicrochannelflowsusingthedirect-simulationMonteCarlo(DSMC)method.Inthepresentwork,inversetemperaturesampling(ITS)isusedtodealwithdiatomicgaseousflowandheattransferinamicrochan-nel.Thistechniqueprovidesanapproachtocalculatethemolecularreflectivecharacteristictemperaturefromthemolecularincidentenergyandtheheatfluxatthewallboundary.CoupledwiththeDSMCmethod,thisdiatomicmoleculeITStechniquecanbeusedtotreattheHFSboundaryconditionsintheDSMCmethod.Verificationindicatesthatthepro-poseddiatomicmoleculeITSmethodcanaccuratelysimulatethegaseousflowandheattransfer.InPartIIofthiswork,theproposedmethodisappliedtodemonstrategeneralmicrochannelgaseousflowpropertiesunderuniformheatfluxboundaryconditions.atthesametime,thenewmethodisadoptedtonumericallyinvestigatetheeffectsofwallheatfluxongaseousflowandheattransferproperties.

在介绍螺旋折流板管壳式换热器的结构及原理的基础上，对壳程传热强化及阻力特性的研究现状进行了总结，分析了壳侧流体的流动和换热机理，表明螺旋折流板结构是改善壳侧流动换热性能的有效措施与弓型折流板换热器相比，螺旋折流板换热器的最大特点是单位压降下的壳侧换热系数高。结合具体实例介绍了其在石油化工、能源动力及核能应用等行业中的应用前景。关于螺旋折流板换热器，还有许多问题需要进一步研究，如流动换热的机理以及影响流动换热机理的几何因素、相变情形、介质物性等。

Numerical computations were performed for the average Nusselt number at an internal vertical plate situated in a square enclosure, with the inner plate and the bounding wall of the enclo-sure maintained at uniform but different temperatures. Natural con-vection occurred in the air which occupied the enclosure space. The position of the inner vertical plate within the enclosure was varied parametrically. The plate height-cavity height ratio was 0.513. For narrow distance between the inner plate and the bounding wall the inner plate Nusselt number was enhanced. Aside from this, the plate average Nusselt number was remarkably insensitive to the plate position. The effect of the Rayleigh number on the velocity and temperature fields and local Nusselt numbers are also discussed. The agreement between the predicted flow pattern for Ra=1.1

In this paper, a SIMPLE-like algorithm on collocated grid system has been developed. The ability to suppress the spurious pressure field is achieved via introducing the pressure difference between adjacent two grid points into the convection-diffusion finite difference scheme, and the interfacial velocity is obtained by simple linear interpolation. The differencing scheme, discretization of governing equations and solution procedure of the algorithm are described in detail. In order to check the validity of the algorithm, several test cases which have analytical or benchmark solutions are presented. Good agreements are obtained between the numerical and the corresponding analytical or benchmark solutions. The ability of the improved algorithm to suppress the spurious pressure field is demonstrated via a 3-D example.