Simulation Study on the Non-Uniform Characteristics of Boiling Flow and Heat Transfer in Parallel Small ChannelsOA

With the sharp increase in the heat flux of high-power electronic devices,efficient thermal management has become critically important.Boiling heat transfer in parallel small channels,which utilizes latent heat efficiently,has emerged as a key enabling technology for next-generation cooling solutions.However,parallel channel systems are extremely susceptible to flow instabilities,resulting in severely uneven distributions of flow rate and heat transfer among the channels.This unevenness often leads to local overheating,which in turn restricts the system''s reliability and limits its practical application.In this paper,a three-dimensional transient numerical simulation method was employed to investigate the non-uniform characteristics of flow boiling and heat transfer of Rl34a within parallel rectangular small channels.The differential characteristics of flow and heat transfer parameters among channels under varying mass flux and heat flux conditions were systematically investigated.The quantitative characterization methods for the degree of flow and heat transfer non-uniformity were proposed.Two quantitative characterization parameters,β_(1)for flow non-uniformity andβ_(2)for heat transfer non-uniformity,are proposed.Besides,the predictive correlations for the nonuniformity degrees of flow and heat transfer were constructed.Theβ_(1)increases with increasing heat flux and decreases with increasing mass flux,whileβ_(2)decreases with increasing heat flux and mass flux.When the mass flux is constant,β_(1)decreases with increasingβ_(2),and the decreasing rate ofβ_(1)is much lower than the increasing rate ofβ_(2).When the heat flux is constant,β_(1)increases with increasingβ_(2),and the increasing rate ofβ_(1)is much larger than the increasing rate ofβ_(2).β_(1)andβ_(2)obtained from simulations agree with the fitted predictions to within±20%.This paper has important theoretical guiding significance for optimizing the safe and stable operation of high heat flux cooling systems.