A Simulation-Based Optimized Design Of A Pt Thin Film Micro Heater And Its Boiling Experimental Research

With the increasing development of science and technology,people’s research on heat transfer has gradually shifted from macro scale to micro scale.In view of the requirements for local temperature control capability of microheaters,this paper aims at developing a MEMS based Pt film microheater.For this purpose,three different shapes of the Pt thin film resistive microheaters was designed,with theirfeature sizes ranging from 3 to 100μm.Based on the finite element analysis,we found that one kind of microheater design showed the fastest temperature riseamong the others.Finally,an experimental system was established to carry out a preliminary study on the transient pulse boiling phenomenon on the microheater.Its main contents are as follows:First,on the basis of literature research,three kinds of micro-heaters with dif ferent shapes are designed,namely bar shape,dumbbell shape and snake shape.T hen,by using ANSYS simulation software,transient heat transferprocess of thes e three different shapes of micro-heaters is carried out.It shows that the microhe ater with dumbbell shape has a fast temperature rise response time and distinct lo cal energy concentration.In addition,by analyzing the simulation results,the further optimization of the micro thin film heater includes:1)selection of substrate materials,2)increasing the thickness of the SiO₂ layer between the Pt thin film micro-heater and the substrate layer,3)changes in the structure of the Pt thin film:the surface of Pt thin film microheater could be designed to have a cantilever structure.The above optimized design can greatly improve the thermal efficiency of the microfilm heater so that the narrow structure can gather energy better.Secondly,the micro fabrication process design of the the microheater was car ried out,and was introduced in detail.A series of dumbbell microheater arrays wi th different size were microfabricated for experiment.Then an experimental platform for transient pulse boiling research is built up.The experimental software parts are mainly Labview,Matlab,etc..The hardware parts mainly include CCD cameras,microscope,DC power supplies,designed control circuits,and microfilm heaters.The boiling phenomenon of the surface of the microheater under the pulse heating is studied,the image data is recorded,and the bubble dynamics process of the phenomenon is analyzed.Then the experimental parameters are substituted into the calculation model to obtain the transient temperature rise curve of the microheater.Thus the reasonable and feasible simulation is obtained.Finally,this paper discusses the limitations and improvement methods of the present research work.