October 15, 2020 at 12:45 pmRajasekarK123SubscriberOctober 15, 2020 at 1:02 pmDrAmineAnsys EmployeeAre you injecting enough particles? What about your computational grid? Which sub-models are activated? What is the definition of your particles in terms of composition?nOctober 16, 2020 at 5:21 amRajasekarK123SubscriberI am injecting single particle(0.2 NaCl and 0.8 water) water is set to evaporate and NaCl not. Energy is ON, Turbulance model is Realizable K- epsilon, Species transport ON, DPM is ON and set to 10 interactions with continuous phase after established continuous flow field. nOctober 16, 2020 at 5:23 amRajasekarK123SubscriberI did face mesing for an axisymmetric domain. the domain size is 0.6 m in length and 0.125m in height. i meshed with 1mm mesh size.nOctober 16, 2020 at 10:37 amRobAnsys EmployeePlease can you post images of the fluid temperature. How big is the droplet? nOctober 16, 2020 at 11:31 amDrAmineAnsys Employeeas well as the multicomponent droplet properties.nOctober 16, 2020 at 3:39 pmRajasekarK123Subscriber(Nacl (fluid droplet-particle)ntt(chemical-formula . Nacl)ntt(density (constant . 2160))ntt(specific-heat (constant . 88))ntt(thermal-conductivity (constant . 0.574))ntt(viscosity (constant . 0.001))ntt(dpm-surften (constant . 0.063))ntt(molecular-weight (constant . 58.44))ntt(reference-temperature (constant . 298.15))ntt(volatile-fraction (constant . 0.01))ntt(binary-diffusivity (constant . 1.57e-9))nt)nnt(Nacl-water (particle-mixture)ntt(species (names h2o Nacl))nOctober 16, 2020 at 3:41 pmRajasekarK123Subscriberthe droplet diameter is 1.8mm nOctober 16, 2020 at 3:58 pmOctober 16, 2020 at 4:01 pmDrAmineAnsys EmployeeNot enough: screenshot from the panel of multicomponent particles to check what is set there. Is the case two-way coupled? If node based averaging is enabled please disable it. Just use Linearize Source Terms instead.nOctober 16, 2020 at 4:04 pmRajasekarK123Subscriberwhen i keep higher temperature difference between the droplet and ambient the solution looks good but having low temperature difference causes the drop in temperaturenOctober 16, 2020 at 4:05 pmOctober 16, 2020 at 4:06 pmOctober 16, 2020 at 4:10 pmRajasekarK123SubscriberAFTER LINEARIZING SOURCE TERM SAME RESULTS OBTAINEDnOctober 16, 2020 at 4:19 pmRajasekarK123SubscriberOctober 19, 2020 at 5:00 amRajasekarK123SubscriberSir, I am expecting your kind help for finishing the work, please help me.nOctober 19, 2020 at 6:02 amDrAmineAnsys EmployeeWhich case on the customer portal? I will need to check it.nOctober 19, 2020 at 6:18 amDrAmineAnsys EmployeeLet me describe what can be realistic: droplet will heated till it reaches the vaporization temperature stars the law 2 then law 3. The latent heat is provided from continuous phase, temperature is reduced of the gas phase which might affect the droplet too if caught in re-circulation region or has a large stokes numbers. Same might happen with MM particle. But the change should not be dramatic for that reason: if you have seeing the behavior on a case from the customer portal please share with us the case / solution number.nnWorth testing though with update source terms every iteration / transient particle tracking.nOctober 19, 2020 at 7:12 amRajasekarK123SubscriberI wil provide the link of that case file here sirnOctober 19, 2020 at 7:15 amRajasekarK123SubscribernOctober 19, 2020 at 7:17 amRajasekarK123Subscriberthe solution number is 2046025nOctober 19, 2020 at 7:20 amRajasekarK123SubscriberI found a reason for the temperature reduction from a journal https://journals.ametsoc.org/jas/article/8/2/71/37827/THE-EVAPORATION-TEMPERATURE-AND-THERMAL-RELAXATION which says the droplet will reach the wet bulb temperature of the air to evaporate.nI am not confirm about the results, but the justification is somewhat acceptable.nKindly help me whether its correct or notnOctober 19, 2020 at 7:27 amDrAmineAnsys EmployeeAre you a commercial customer? Have you read my explanation? I will look in the files. Please be patient. nOctober 19, 2020 at 7:49 amRajasekarK123SubscriberYes sir, now reading your previous explanation. nOctober 19, 2020 at 9:09 amDrAmineAnsys EmployeeFiles are looking good and are in line with my explanation.nOctober 19, 2020 at 9:15 amRajasekarK123Subscribersir did you check that with temperature modification like particle temperature 300 and air temperature 301. did you observe temperature reduction of particle?nOctober 19, 2020 at 10:10 amRobAnsys EmployeeHow big is the cell the droplet is injected into? Remember the droplet is tracked as a point mass but dumps all of it's evaporated mass & removes ALL of the energy needed to do this into one cell. If the droplet is bigger than the cell interesting things happen to the results. nOctober 19, 2020 at 10:27 amRajasekarK123SubscriberDear Rob, The droplet size is 1.5 mm, cell size is 1 mmnOctober 19, 2020 at 10:32 amRajasekarK123SubscriberAny way I checked with the case file given by ansys and all the parameters are same in the case file but changing only the temperature makes these reduction in drop temperaturenOctober 19, 2020 at 10:37 amRobAnsys EmployeeDecrease the droplet diameter to 0.01mm and see what happens. nOctober 19, 2020 at 11:16 amRajasekarK123Subscribersame reduction in temperature is observed. no change in the patternnOctober 19, 2020 at 2:47 pmDrAmineAnsys EmployeeStill willing to know what do you expect? The gas is cooled as we are evaporating, now the cooled gas is in the contact with the non volatile part of the particle, heat exchange-> droplet is cooled. Also check the change of heat sing in the dpm summary: A positive Change of Heat denotes that heat is expelled from the continuous phase and absorbed by the particle, while a negative Change of Heat denotes heat is released by the particle to the continuous phase.nnDouble check if the sum of the DPM Enthalpy Source is in the same magnitude range as the one from the DPM summary (with negative sign)nOctober 20, 2020 at 5:22 amRajasekarK123SubscriberThank you Amine sir for your kind explanation for all my queries. nViewing 32 reply threads
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