Heat Transfer Characteristics Research of Screw Thread Swirling Impinging Jets Based on Numerical Simulation Method[J]. 2017, 51(9): 11-18.
DOI:
Heat Transfer Characteristics Research of Screw Thread Swirling Impinging Jets Based on Numerical Simulation Method[J]. 2017, 51(9): 11-18.DOI: 10.7652/xjtuxb201709002.
Heat Transfer Characteristics Research of Screw Thread Swirling Impinging Jets Based on Numerical Simulation Method
To improve the uniformity of traditional impinging jet heat transfer
a new type of jet structure with some circumferential spiral channels set inside the normal nozzle
like the internal thread
is proposed in this paper. First
several numerical methods are adopted to process the experimental data of the swirling impinging jet from a swirl generator
and the data are referenced from a published literature. Results show that the RNG k-ε turbulence model is more suitable for simulation of the swirling impingement jet. Then
the effects of such parameters as Reynolds number(4 000-12 000)
impact distance(1-8 times of equivalent diameter)and helix angle(0°-75°)on the heat transfer performance of such threaded hole are studied. The research is focused on the flow field and heat transfer characteristics. The experimental results indicate that the heat transfer rate and the uniformity of impinging target will increase with the Reynolds number
and the local Nusselt number will increase first and then decrease with the increasing impact distance. Meanwhile
the double-peak feature of the local Nusselt number will change to single-peak shape
and the maximum local Nusselt number can be obtained at the 4-fold equivalent diameter. The local Nusselt number at the center point will increase with the helix angle
but the heat transfer uniformity will be worse. In addition
it is found that the helix angle corresponding to the best heat transfer performance also changes with different impact distances.
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