Numerical Analysis Of The Flow Distribution In Multiple Branches Parallel-tube Configuration

Flow distribution in multi-branch parallel channels has widely engineering application,and U-type and Z-type arrangements are classical parallel channel models for the practicalengineering application. These two forms are common flow distribution devices inpetrochemical, thermal power, boilers, solar energy, nuclear power, refrigeration and otherimportant areas. The fluid flow characteristics (such as rate, flow distribution, etc.) in parallelchannel directly relate to the security and economy of the equipment, and are very importantfor design of the flow distributors. Thus it is very valuable to study flow distributioncharacteristics in multi-branch parallel channels. In this paper, the physical model of flowdistribution is established, and three-dimensional numerical method is used to solve modeland investigate the flow characteristics under different flow conditions and differentgeometric parameters of channel.The contents of present study includes: using FORTRAN language and infiniteinterpolation method to generate numerical grid for Z-type multi-branch parallel pipelinesystem; using SIMPLE algorithm under pressure boundary conditions to investigate the flowcharacteristics in parallel piping system; analyzing the effect of different pressure dropbetween the inlet and the outlet of manifold and different diameter of the manifold on theflow characteristics; providing the characteristics of the parameters, such as the axialmomentum recovering coefficient, the lateral momentum recovering coefficient, the localpressure drop factor, and velocity ratio in the manifold.The results show that the pressure drop between the inlet and the outlet of the manifoldhas an important influence on the flow distribution, and the diameter of the manifold has greateffect on the flow distribution. Increasing the manifold diameter can get better flowdistribution. The axial momentum recovering coefficient has a wavy increase along the flowdirection in the distributor, and decreases gradually in the collector. The lateral momentumrecovering coefficient increases at nine interfaces of the branch and the distributor, however,it declines in the tenth interface. The lateral momentum recovering coefficient at theinterfaces between the branch and the collector increases firstly and decreases later. Thecharacteristics of the axial velocity ratio in every branch pipe on the interfaces almost keepthe same as that of the lateral momentum recovering coefficient, and only slightly different.The numerical result shows that the local friction factor increases along the flow direction inthe distributor, and decreases along the flow direction in the collector. The friction factorchanges drastically near the inlet of every branch pipe, and when fluid flow passes throughthe vortex region and develops fully, the friction factor is constant. The study also provides anew numerical method that can obtain the flow distribution in manifolds.