ABSTRACT: The slotted fin concept was employed to improve the air cooling performance of plate-fin in heat sinks. Numerical simulations
of laminar heat transfer and flow pressure drop were conducted for the integral plate fin, discrete plate fin and discrete
slotted fin heat sinks. It is found that the performance of the discrete plate fin is better than that of the integral continuum
plate fin and the performance of slotted fin is better than that of the discrete plate fin at the same pumping power of the
fan. A new type of heat sink characterized by discrete and slotted fin surfaces with thinner fins and smaller spaces between
fins is then proposed. Preliminary computation shows that this type of heat sink may be useful for the next generation of
higher thermal load CPUs. The limit of cooling capacity for air-cooling techniques was also addressed.
Frontiers of Energy and Power Engineering in China 04/2012; 2(2):158-163.
ABSTRACT: In the present paper, the classical pressure correction method was extended into low Mach number compressible flow regime
by integrating equation of state into SIMPLE algorithm. The self-developed code based on this algorithm was applied to predicting
the lid-driven cavity flow and shock tube problems, and the results showed good agreement with benchmark solutions and the
Mach number can reach the magnitude of as low as 10−5. The attenuation of sound waves in viscous medium was then simulated. The results agree well with the analytical solutions
given by theoretical acoustics. This demonstrated that the present method could also be implemented in acoustics field simulation,
which is crucial for thermoacoustic simulation.
Science in China Series E Technological Sciences 04/2012; 52(6):1583-1595. · 1.02 Impact Factor
ABSTRACT: In this paper, analytic relations between the macroscopic variables and the
mesoscopic variables are derived for lattice Boltzmann methods (LBM). The
analytic relations are achieved by two different methods for the exchange from
velocity fields of finite-type methods to the single particle distribution
functions of LBM. The numerical errors of reconstructing the single particle
distribution functions and the non-equilibrium distribution function by
macroscopic fields are investigated. Results show that their accuracy is better
than the existing ones. The proposed reconstruction operator has been used to
implement the coupling computations of LBM and macro-numerical methods of FVM.
The lid-driven cavity flow is chosen to carry out the coupling computations
based on the numerical strategies of domain decomposition methods (DDM). The
numerical results show that the proposed lifting relations are accurate and
ABSTRACT: The segregated algorithm-IDEAL (inner doubly-iterative efficient algorithm for linked-equations) is an efficient and stable
algorithm. In this algorithm, there exist inner doubly-iterative processes for pressure equation, which almost completely
overcome two approximations in SIMPLE algorithm. Thus the coupling between velocity and pressure is fully guaranteed, greatly
enhancing the convergence rate and stability of iteration process. In this paper, implementation of the IDEAL algorithm on
a 3D collocated grid system is conducted. The interface velocity is calculated by the modified momentum interpolation method
(MMIM), by which the converged result is independent of the under-relaxation factor. Finally, five three-dimensional incompressible
fluid flow and heat transfer problems are provided to compare the convergence rate and robustness between the IDEAL and three
other most widely-used algorithms (SIMPLER, SIMPLEC and PISO). By the comparison it can be concluded that the IDEAL algorithm
is more robust and efficient than the three other algorithms.
Chinese Science Bulletin 02/2009; 54(6):929-942. · 1.32 Impact Factor
ABSTRACT: A three-dimensional physical and numerical model of the basic pulse tube refrigerator (PTR) was developed. The compressible
and oscillating fluid flow and heat transfer phenomenon in the pulse tube were numerically investigated using a self-developed
code. Some cross-section average parameter variations such as velocity, temperature and pressure wave during one cycle were
revealed. The variations of velocity and temperature distributions in the pulse tube were also analyzed in detail for further
understanding of the working process and refrigeration mechanism of PTRs.
Frontiers of Energy and Power Engineering in China 01/2008; 2(1):48-53.