The effect of pressure on heat transfer at evaporation/boiling in horizontal liquid layers of various heights on a microstructured surface produced by 3D laser printing

Experimental study of heat transfer during boiling in a thin layer of liquid on surfaces with structured porous coatings

“…The upper points of the boiling curves correspond to the CHF. In the evaporation regime, which in Figure 2 corresponds to the data at 133 Pa, "funnels" [3] were formed on the stainless steel surface up to the values of heat fluxes q = 10 kW/m 2 . "Funnels" are the depressions with a hemispherical bottom in a thin layer of liquid.…”

“…With an increase in the heat flux, the liquid layer on the stainless steel surface evaporated gradually, and the heat transfer coefficient at the same time assumed a constant value in the range of heat fluxes q = 10-13.4 kW/m 2 until the layer completely evaporated and the dryout crisis occurred. On the bronze coating, when a certain heat flux q = 10 kW/m 2 was reached, "craters" [3] appeared in the liquid layer. "Craters" are recesses on the surface of a liquid layer; there is a long flat residual liquid layer of finite sizes in the centers of the cavities.…”

“…The task of reducing the temperature head, that is, enhancing heat transfer, becomes especially important. However, in [3,4], it is shown that the influence of pressure on the CHF during evaporation and boiling on the modified surface has a complex character in a thin layer of liquid. It is found that with increasing pressure, the CHF value decreases.…”

Development of Methods for Heat Transfer Enhancement During Nitrogen Boiling to Ensure Stabilization of HTS Devices

“…In [151,152], the application of the method of selective layer-by-layer laser sintering of metal powder for deposition of capillary-porous coatings with a given porosity on heat-transfer surfaces is considered. It is shown that the use of this technology can increase the boiling HTC on a coated surface several times as compared with an uncoated surface.…”

“…The authors of these works have shown that the HTC on a surface with a capillary-porous coating is approximately 3-5 times higher than that on a surface without a coating. In [151,152], experiments on boiling in thin horizontal layers of n-dodecane liquid were conducted with practically the same profiles of micro-structured capillary-porous coatings as in [88,89,115], where the heat-release surface in experiments with boiling liquid nitrogen was modified by the above-mentioned method of directional plasma spraying.…”