Experimental investigation of the effect of heat sink orientation on subcooled flow boiling performance in a rectangular microgap channel

Flow Boiling in Minigap in the Reversed Two-Phase Thermosiphon Loop

“…It receives a working medium in a two-phase state, where its transport takes place on the principle of a steam liquid lifter (similarly as in the mammoth pump). After a part of the two-phase mixture is delivered to the separator (5), the liquid phase flows gravitationally to the bottom of the separator (5) and then, further, down to the pipeline (2) leading to the condenser (6). The vapor flows through a second pipeline (3) in the upper part of the separator (5) and also goes to the condenser (6), partially The experimental facility is an inverted thermosiphon working with a single working fluid which changes phase in the evaporator.…”

“…After a part of the two-phase mixture is delivered to the separator (5), the liquid phase flows gravitationally to the bottom of the separator (5) and then, further, down to the pipeline (2) leading to the condenser (6). The vapor flows through a second pipeline (3) in the upper part of the separator (5) and also goes to the condenser (6), partially condensing along the pipeline (3). In the condenser (6) heat is removed and the working medium is cooled down to the initial temperature.…”

“…To control the heat balance and the heat transport process, the installation was equipped with temperature sensors (T-type thermocouples) at all key points as well as at the length of the pipelines. The mass flow of the working medium (ultrasonic flow meter Titan Atrato 740-V10-RD) is measured on the evaporator's inlet pipeline (7) and on the liquid drainage pipeline (8) from the separator (5). The mass flowrate in the vapor pipeline (3) is estimated based on the balance of the two above indications.…”

“…Particularly of interest are the conditions for flow visualization regarding flat, two-dimensional configurations of flow [2]. Several issues, mentioned in the recent literature, are related to the influence of size [3,4], orientation [5][6][7] and surface [8][9][10][11][12][13] structure of the minigap on heat transfer and pressure drop and also to the passive methods [8,[14][15][16].…”

Experimental and Numerical Investigation of Micro/Mini Channel Flow-Boiling Heat Transfer with Non-Uniform Circumferential Heat Fluxes at Different Rotational Orientations

“…They found that for these conditions, the channel's rotational position had little influence on the heat transfer performance of buoyancy-driven secondary flows. In another study, Ajith Krishnan, et al [37] also experimentally considered flowboiling in vertical upward and downward flows as well as horizontal flow with separate heating from above and below in a single microchannel (microgap) with a width of 20 mm and a height of 0.2 mm and mass fluxes of 303, 610 and 911 kg/m 2 s. Again, it was found that channel orientation had little influence on the heat transfer coefficient. As before, this was attributed to the relatively high mass fluxes, which resulted in insignificant bubble-wall interactions.…”