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1、 CFD modeling of air flow and heattransfer of ice cream cabinetProject Status Report:2013-04-23 Cabinet B-5Outline2Heat transport modelComplex porous material modelSimplified porous material modelNature convectionThermal boundary conditionSummaryOutline3Heat transport modelComplex porous material mo
2、delSimplified porous material modelNatural convectionThermal boundary conditionSummary4Step1: Choose the energy equationStep2: Choose the Viscous Heating option in Viscous Model and materialsStep3: Choose the Thermal in Boundary Condition optionsHow to simulate the heat transportation5In order to fa
3、miliar with the heat transportation, I test how to simulation the heat transportation. Step 1: activate the energy equationThe first test6 Step2: Choose a suitable viscous model1. Choose the K- model and keep the default settings unchanged. 2. Choose the Viscous Heating options.7 Step2：Set the mater
4、ials options8 Choose 2 kinds solid materials from the Fluent database, then change their physical property to those you want. eg.9Step3: set thermal boundary conditionsThe first kind of boundaryconditionCold wall setting10Result of the testTemperature distribution11Velocity distributionOutline12Heat
5、 transport modelComplex porous material modelSimplified porous material modelNatural convectionThermal boundary conditionSummary13Porous material modelBecause the plates between the refrigeration cabinet and the storage room are perforated plates, So I learned how to simulate the perforated plates.S
6、tep1: modify the cabinet model and make it more close to the reality.14Perforated platesFan15Step2: How to set the porous media Set perforated plate areas to fluid type.Choose the porous zone option and set The parameters.16 Define the vector directionIf the model is 3 dimensions, we should set 2 or
7、thotropic directions.17 Define the Viscous Resistance and Inertial Resistance eg.181920Outline21Heat transport modelComplex porous material modelSimplified porous material modelNatural convectionThermal boundary conditionSummary22Simplified porous material model Two disadvantages in the above test:
8、1. The data about the media cannot be evaluated conveniently. 2. It will take more time to simulate.Solution: simplify the porous areas to porous -jump boundary condition. 23How to set the porous-jump boundary condition2425In Fluent software, we set as follow:Outline26Heat transport modelComplex por
9、ous material modelSimplified porous material modelNatural convectionThermal boundary conditionSummary271) Choose incompressible-ideal-gasTwo ways for modeling nature convection:282) Choose the Boussineaq modelI choose the 1st way in the simulation29Thermal boundary condition and result:Temperature d
10、istributionHeat flux=-600WHeat flux=430WHeat flux is the second boundary condition30Velocity distributionCut the model in the middle of Y direction (parallel to X)31The section of temperature distributionCut the model in the middle of Y direction (parallel to X)32Left sideBottom sideRight sideBack s
11、ideOutline33Heat transport modelComplex porous material modelSimplified porous material modelNatural convectionThermal boundary conditionSummaryProblems After above simulation, I also take some other simulations by change the heat flux in the cold wall and the heat flux in the glass wall34Cold wall/
12、WGlass wall/W-500430-430430-370430-270430-100430 I found that the result of simulation have a close relationship with the initial value. When the initial temperature is high, the temperature in the simulation is high. In contrast, when the initial temperature is low, the temperature in the simulatio
13、n is also low. After I have read many reference, I believe that the thermal boundary condition should be changed. 35The third kind boundary condition The third kind boundary condition: Define the heat transfer coefficient between the object and the around space and define the temperature of the arou
14、nd space. How to set in the Fluent:36 The cold wall keep the heat flux boundary condition, while the glass wall change to the convection boundary condition as pervious page How to define the heat transfer coefficient:37 I test the convection boundary condition in the below simulation, but I use the
15、interior boundary condition instead of the porous- jump boundary condition. I will display the result of simulation in the next several pages and I will use porous- jump boundary condition in the following simulation because it close to the reality.3839Velocity distributionTemperature distributionThe section of velocity distribution40Left sideTop sideRight sideBottom side41The section of velocity distribution(where set the fan)parallel to the XZ surfaceparallel to the YZ surfa
