Effects of surface wettability on bubble departure and critical heat flux: A parametric study based on 3-D dynamic force analysis model

A Review of Pool-Boiling Processes Based on Bubble-Dynamics Parameters

“…The forces on the bubble in their mechanical model include the surface tension F S , the liquid pressure F P , the gravity F G , the momentum change force F e , the internal pressure of the bubble F m , the instantaneous expansion force acting on the boundary of the bubble F a , which is oriented perpendicular to the boundary of the bubble, and the combined force acting on the bubble, which was denoted as F Z . The comparison between Wang et al's [52] proposed force model and that of Liu et al [59] is shown in Figure 9, and the computational equations of various forces are shown in Table 3, where H denotes the height from the wall to the liquid surface, β is the ratio of the area of the micro-fluid layer to the area of the bottom of the bubble, q I denotes the heat flux at the gas-liquid interface around the bubble, and S s denotes the area of the gas-liquid interface, with the negative sign indicating that the direction is along the direction of gravity. In its assumptions, the radius of the micro-fluid layer is approximately twice the radius of the dry portion.…”

“…In its assumptions, the radius of the micro-fluid layer is approximately twice the radius of the dry portion. Liu et al [59] calculated the pressure on the bubble surface by spherical coordinate integration, and considered the effect of the micro-liquid layer at the bottom of the bubble on the overall pressure. The receding contact angle α was taken in their calculations, which was obtained by photographing the state of the bubble before it detached.…”

“…In its assumptions, the radius of the micro-fluid layer is approximately twice the radius of the dry portion. [59] proposed bubble-force equations.…”

“…Liu et al [59] proposed the formula p = ρ l gh for liquid pressure, however, the effect of external air pressure should also be taken into account due to the adhesion of the bubbles to the wall, i.e., p = ρ l gh + p 0 . The integration of the actual liquid pressure on the bubbles in combination with the external pressure results in:…”

Analysis of the Causes of the Emergency Shutdown of Natural Gas-Fired Water Peak Boilers at the Large Municipal Combined Heat and Power Plant

“…Current mathematical models do not encompass the impact of bubble formation on the flow and temperature distribution. Attempts are presently being made to simulate these phenomena through numerical methods [26,31], but an accurate model is yet to be developed. Consequently, there is a dearth of simple calculation methods (standards) that designers can use to predict the potential occurrence of such phenomena during the design of boilers and power equipment [32].…”