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Fluent incident radiation problem
Dear Fluent users,
enclosed you receive the collector model, with which we simulated the irradiation on a windowpane. The collector model consists of a rectengular-box, which is flowed through with air. The radiation falls through the windowpane on the rear wall. Thus the rear wall is warmed up and transfers the energy to the air flow. The following boundary conditions were set (see appendix). Incident radiation on glas surface = 1000 W/mē glas area = 1,8 mē glas absorption coefficient band 1 = 32 1/m band 2 = 200 1/m velocity inlet = 0.2 m/s After 350 iterations the simulation converged. The results are as followed (see appendix). Inlet temperature = 300 K outlet temperature = 310 K glas temperature = 303 K wand on backside = 314 K flux report inlet/outlet = - 310 W intergral incident radiation on backside (absorbed energy) = +1788 W energy balance = 1478 W The energy balance is unfortunately not correct. The windowpane is impermeable for infrared radiation (Coeff=200 1/m). The absorber can therefore lose no energy to the environment by radiation. As a test we put the irradiation directly as a heat flux on the absorber and set the windowpane on diffuse. Now the air flow experiences a rise in temperature of about 80 K - this is realistic. Can someone help me with this problem ?? Thanks for help, Michael Schwarz Attachment: File testfall_dsplan.cas zone 2 (velocity_inlet.1): 0.024500012 zone 3 (pressure_outlet.2): -0.024499377 zone 4 (glasscheibe): 0 zone 5 (wandhinten): 0 zone 6 (wand_rechts): 0 zone 7 (wand_links): 0 zone 8 (wall): 0 zone 10 (default-interior): -1.1677017 net mass-flow: 6.35162e-07 zone 2 (velocity_inlet.1): 29.449089 zone 3 (pressure_outlet.2): -339.33804 zone 4 (glasscheibe): 0 zone 5 (wandhinten): 0 zone 6 (wand_rechts): 0 zone 7 (wand_links): 0 zone 8 (wall): 0 net heat-transfer: -309.88895 zone 2 (velocity_inlet.1): -11.843837 zone 3 (pressure_outlet.2): -33.356339 zone 4 (glasscheibe): 310.07889 zone 5 (wandhinten): -215.85818 zone 6 (wand_rechts): -16.41909 zone 7 (wand_links): -16.419128 zone 8 (wall): -16.041611 net rad-heat-transfer: 0.14069843 Integral Incident Radiation (glasscheibe): 1833.0248 Integral Incident Radiation (wandhinten): 1784.6536 Integral Incident Radiation (wand_rechts): 829.83936 Integral Incident Radiation (wand_links): 829.83936 Average Static Temperature (velocity_inlet.1): 300.06528 Average Static Temperature (pressure_outlet.2): 310.11212 Average Static Temperature (glasscheibe): 302.96265 Average Static Temperature (wand_links): 307.0737 Average Static Temperature (wand_rechts): 307.07373 Average Static Temperature (wandhinten): 314.14886 |
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