Reduced-order model of proper orthogonal decomposition method (POD) was established to analyzed performance of fluid flow and heat transfer in flat tube bank fin heat exchanger. Numerical results of POD were compared with those of FVM. It indicates that average relative error between POD results and FVM results is no more than 5.7% while computational speed is improved 164.78-2021 times. Conclusion is of theoretical meaning for optimizing heat exchanger structure and running mode in engineering.

We study carbonation process of CaO with lattice Boltzmann method. Specifically,effects of porosities of CaO particles on carbonation rate are investigated. It shows that efficiency depends on porosity nonlinearly due to competition between molar mass and permeability of particles.

A detailed comparative study is made to investigate three boundary treatment schemes in lattice Bohzmann methods (LBM).They are half-way bounce back scheme,sub-grid scheme,and a scheme to treat curved boundaries.It is found that particle translational and angular velocities calculated with half-way bounce back scheme oscillate strongly,while particle velocities obtained by sub-grid scheme evolve smoothly.

An explicit equation for critical quantity of heat in condensing flow in a shock tube was derived.The equation is of general validity and applies tO vapor flow with or without cagier gas.It shows that critical quantity of heat in internal heat flow for phase change is greater than external heat flow.As flow is choked thermally,a shock wave is generated and propagates upstream.A location where local static pressure begins to rises,which has long been regarded as onset of unsteady condensation in a steady supersonic nozzle,is not acceptable in shock tube flow.It is before the zone of condensation.Furthermore,a second-order AUSM scheme is applied tO two-dimensional compressible flow with condensation.Computation results reproduce integral predictions well.

Generalized coarse-mesh finite difference(GCMFD) method,which uses generalized-geometry coarse meshes to speed up the method of characteristics(MOC),is proposed.A method adjusting width factor automatically is adopted in the GCMFD method.The GCMFD method is adopted in a 3-D neutron transport MOC code TCM.Numerical tests are used to verify acceleration effect of GCMFD in TCM.It shows that the GCMFD method can use generalized-geometry coarse meshes to accelerate MOC iteration,and the GCMFD method with automatically adjusting width factor has good acceleration effect.

According to the characteristics of perfectly matched layers (PML), a convolutional PML (CPML) is chosen to truncate open boundaries used in the numerical simulation of low-altitude electromagnetic pulse. On the basis of the split-field PML and the plane-wave solution of electromagnetic field in a free space, an unsplit-field PML is constructed. With convolutional theorem in the Fourier transformation, discerete iterative equations of electromagnetic field components in the CPML media are presented in three-dimensional prolate-spheroidal coordinate system. The effectiveness of the method in numerical simulation of nuclear electromagnetic pulse is shown.

The laminar flow and heat transfer of water in periodic fully-developed divergent-convergent channels has been investigated numerically.The SIMPLE algorithm and body-fitted coordinates (BFC) are used.The periodic boundary condition is treated using the method proposed by Amano.It is found that under the range of Re=100~1 000,the friction factor is about 10%~200% more than that of parallel plate channel,while the average Nusselt number is about 40%~320% more than that of parallel plate channel.

Many-body perturbation theory is employed in a study of the electronic structure of the transition metal atoms through second-onder in the energy. The basis sets consist of STO[8s6p4d1f]. The agreement with experiment is good for Cr atom.