Loop Heat Pipes (LHPs) are used in many thermal management applications, especially for micro-electronics noting, because of their ability to passively transport thermal mergy from a source to a sink. This paper describes the development of a parametric model for a non-conventional JiP operating in steady state, employed to cool Light Emitting Diodes (LEDs). This device is comprised of a flat evaporator, and a finned circular loop wherein condensation and sub-cooling of the working fluid takes place. Unlike a conventional LHP, this device has no compensation chamber. In the mesh xreen of the evaporator, the vapor flow entrains liquid andthe quality of the two-phase mixture leaving the toapomtor (x_(evap)) is less than unity (unlike in a conventional utP where saturated vapor leaves the evaporator). Since this wer quality (approximately 0.2) results in a smaller ratio of ""en/ energy to sensible energy being removed by the ^denser and sub-cooler respectively; the ratio of the length tfthe sub-cooler to condenser length is significantly larger. This results in more stable and controlled operation of thedevice. Mathematical models of the evaporator, the condenser and the sub-cooler sections are developed, and two closure conditions are employed in this model. For consistency and accuracy, some parameters in the model, such as the natural Section heat transfer coefficient (h 0) and a few thermal Stances in the evaporator, are estimated empirically from data on the device. The empirically obtained value of theheat transfer coefficient is in very good agreement with correlations from the literature. The parametric model accurately predicts the LED board temperature and other temperatures for a specific amount of thermal energy dissipated by the LEDs.KNon-Conventional Loop Heat Pipes;;Entrainment;;Parametric model;;cooling LEDs
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