Research On The Mechanism Of Industrial Waste Heat Recovery Using High Efficient Phase Change Technology

As representative of the high-energy consumption industry, the process industry waste heat resources are urgently recycled. However, related technology and theoretical research is still in its infancy, and the low temperature industrial waste heat can’t be recycled efficiently. The functionally latent thermal phase change nanofluid microchannel waste heat recovery unit is the most advanced waste heat recovery technology to solve this technology problem, however, its industrial application still exists many key scientific issues needing to be studied. Figuring out the abnormal flow and the heat transfer enhancement mechanism of the functionally latent thermal phase change nanofluid is the theory premise to recycle the industrial waste heat efficiently, and is important significance to develop the efficient recovery technology and device of industrial waste heat with our country intellectual property rights, and to energy saving and environmental protection in China. Therefore, the heat transfer enhancement mechanism of the laminar flow with the functionally latent thermal phase change nanofluid in the microchannel and the waste heat recovery mechanism of the functionally latent thermal phase change nanofluid microchannel waste heat recovery unit are investigated by means of numerical simulation in this paper. The results are as following:(1) Based on the organic combination of the field synergy principle of heat transfer enhancement and the functionally latent thermal phase change nanofluid, the heat transfer enhancement mechanism and the numerical simulation adaption to flow and heat transfer problems of the functionally latent thermal phase change nanofluid in microchannels was established.(2) The study has shown that, In both constant heat flux and constant wall temperature condition, the heat transfer enhancement effect of the functionally latent thermal phase change nanofluid in microchannels increases with the increase of the PCM nanoparticle volume concentration c, the melting latent heat LH, and Reynolds number Re. The influence of the Initial supercooling degree Ti-Ts and the phase change temperature range TL-TS is not very obvious. (3) The study has shown that, with respect to traditional single-phase fluid microchannel waste heat recovery unit, The functionally latent thermal phase change nanofluid microchannel waste heat recovery unit has significantly enhanced heat transfer effect, the heat enhancement effect of the functionally latent thermal phase change nanofluid microchannel waste heat recovery unit increases with the increase of the PCM nanoparticle volume concentration c, the melting latent heat LH, and the fluid flow velocity u increasing. When c=25%and LH=271kJ/kg, the heat enhancement effect is as high as34.9%and39.16%respectively. Improving c, LH and u is beneficial to strengthen the heat enhancement effect of the functionally latent thermal phase change nanofluid microchannel waste heat recovery unit.