Experimental and Numerical Analysis of the Influence ofMicrochannel Size and Structure on Boiling Heat Transfer

Computational fluid dynamics was used and a numerical simulation analysis of boiling heat transfer in microchannels with three depths and three cross-sectional profiles was conducted.The heat transfer coefficient and bubble generation process of three microchannel structures with a width of 80μm and a depth of 40,60,and 80μm were compared during the boiling process,and the factors influencing bubble generation were studied.A visual test bench was built,and test substrates of different sizes were prepared using a micro-nano laser.During the test,the behavior characteristics of the bubbles on the boiling surface and the temperature change of the heated wall were collected with a high-speed camera and a temperature sensor.It was found that the microchannel with a depth of 80μm had the largest heat transfer coefficient and shortest bubble growth period,the rectangular channel had a larger peak heat transfer coefficient and a lower frequency of bubble occurrence,while the V-shaped channel had the shortest growth period,i.e.,the highest frequency of bubble occurrence,but its heat transfer coefficient was smaller than that of the rectangular channel.

A Lifting Method for Krause's Consensus Model

In this work,we aim to show how to solve the continuous-time and continuous-space Krause model by using high-order finite difference(FD)schemes.Since the considered model admits solutions withδ-singularities,the FD method cannot be applied directly.To deal with the annoyingδ-singulariti-es,we propose to lift the solution space by introducing a spltting method,such that theδ-singularities in one spatial direction become step functions with dis-continuities.Thus the traditional shock-capturing FD schemes can be applied directly.In particular,we focus on the two dimensional case and apply a fifth-order weighted nonlinear compact scheme(WCNS)to ilustrate the validity of the proposed method.Some technical details for implementation are also presented.Numerical results show that the proposed method can captureδ-singularities well,and the obtained number of delta peaks agrees with the the-oretical prediction in the literature.