Assessment of Different CFD Modeling and Solving Approaches for a Supersonic Steam Ejector Simulation
The effects of different modeling and solving approaches on the simulation of a steam ejector have been investigated with the computational fluid dynamics (CFD) technique. The four most frequently used and recommended turbulence models (standard <i>k</i>-<i>ε</i>, RNG <i&g...
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| Format: | Article |
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MDPI AG
2022-01-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/13/1/144 |
| _version_ | 1797495796709457920 |
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| author | Jingshu Xiao Qiao Wu Lizhou Chen Weichang Ke Cong Wu Xuelong Yang Liangying Yu Haifeng Jiang |
| author_facet | Jingshu Xiao Qiao Wu Lizhou Chen Weichang Ke Cong Wu Xuelong Yang Liangying Yu Haifeng Jiang |
| author_sort | Jingshu Xiao |
| collection | DOAJ |
| description | The effects of different modeling and solving approaches on the simulation of a steam ejector have been investigated with the computational fluid dynamics (CFD) technique. The four most frequently used and recommended turbulence models (standard <i>k</i>-<i>ε</i>, RNG <i>k</i>-<i>ε</i>, realizable <i>k</i>-<i>ε</i> and SST <i>k</i>-<i>ω</i>), two near-wall treatments (standard wall function and enhanced wall treatment), two solvers (pressure- and density-based solvers) and two spatial discretization schemes ( the second-order upwind scheme and the quadratic upstream interpolation for convective kinematics (QUICK) of the convection term have been tested and compared for a supersonic steam ejector under the same conditions as experimental data. In total, more than 185 cases of 17 different modeling and solving approaches have been carried out in this work. The simulation results from the pressure-based solver (PBS) are slightly closer to the experimental data than those from the density-based solver (DBS) and are thus utilized in the subsequent simulations. When a high-density mesh with <i>y</i><sup>+</sup> < 1 is used, the SST <i>k</i>-<i>ω</i> model can obtain the best predictions of the maximum entrainment ratio (ER) and an adequate prediction of the critical back pressure (CBP), while the realizable <i>k</i>-<i>ε</i> model with the enhanced wall treatment can obtain the best prediction of the CBP and an adequate prediction of the ER. When the standard wall function is used with the three <i>k</i>-<i>ε</i> models, the realizable <i>k</i>-<i>ε</i> model can obtain the best predictions of the maximum ER, and the three <i>k</i>-<i>ε</i> models can gain the same CBP value. For a steam ejector with recirculation inside the diffuser, the realizable <i>k</i>-<i>ε</i> model or the enhanced wall treatment is recommended for adoption in the modeling approach. When the spatial discretization scheme of the convection term changes from a second-order upwind scheme to a QUICK scheme, the effect can be ignored for the maximum ER calculation, while only the CBP value from the standard <i>k</i>-<i>ε</i> model with the standard wall function is reduced by 2.13%. The calculation deviation of the ER between the two schemes increases with the back pressure at the unchoked flow region, especially when the standard <i>k</i>-<i>ε</i> model is adopted. The realizable <i>k</i>-<i>ε</i> model with the two wall treatments and the SST <i>k</i>-<i>ω</i> model is recommended, while the standard <i>k</i>-<i>ε</i> is more sensitive to the near-wall treatment and the spatial discretization scheme and is not recommended for an ejector simulation. |
| first_indexed | 2024-03-10T01:54:42Z |
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| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-10T01:54:42Z |
| publishDate | 2022-01-01 |
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| series | Atmosphere |
| spelling | doaj.art-1de360c21a3e4209883915d6522f7fbc2023-11-23T12:57:54ZengMDPI AGAtmosphere2073-44332022-01-0113114410.3390/atmos13010144Assessment of Different CFD Modeling and Solving Approaches for a Supersonic Steam Ejector SimulationJingshu Xiao0Qiao Wu1Lizhou Chen2Weichang Ke3Cong Wu4Xuelong Yang5Liangying Yu6Haifeng Jiang7China Tobacco Hubei Industrial LLC, Wuhan 430072, ChinaChina Tobacco Hubei Industrial LLC, Wuhan 430072, ChinaHubei Xinye Reconstituted Tobacco Development Co., Ltd., Wuhan 430072, ChinaChina Tobacco Hubei Industrial LLC, Wuhan 430072, ChinaChina Tobacco Hubei Industrial LLC, Wuhan 430072, ChinaSchool of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, ChinaSchool of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, ChinaSchool of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, ChinaThe effects of different modeling and solving approaches on the simulation of a steam ejector have been investigated with the computational fluid dynamics (CFD) technique. The four most frequently used and recommended turbulence models (standard <i>k</i>-<i>ε</i>, RNG <i>k</i>-<i>ε</i>, realizable <i>k</i>-<i>ε</i> and SST <i>k</i>-<i>ω</i>), two near-wall treatments (standard wall function and enhanced wall treatment), two solvers (pressure- and density-based solvers) and two spatial discretization schemes ( the second-order upwind scheme and the quadratic upstream interpolation for convective kinematics (QUICK) of the convection term have been tested and compared for a supersonic steam ejector under the same conditions as experimental data. In total, more than 185 cases of 17 different modeling and solving approaches have been carried out in this work. The simulation results from the pressure-based solver (PBS) are slightly closer to the experimental data than those from the density-based solver (DBS) and are thus utilized in the subsequent simulations. When a high-density mesh with <i>y</i><sup>+</sup> < 1 is used, the SST <i>k</i>-<i>ω</i> model can obtain the best predictions of the maximum entrainment ratio (ER) and an adequate prediction of the critical back pressure (CBP), while the realizable <i>k</i>-<i>ε</i> model with the enhanced wall treatment can obtain the best prediction of the CBP and an adequate prediction of the ER. When the standard wall function is used with the three <i>k</i>-<i>ε</i> models, the realizable <i>k</i>-<i>ε</i> model can obtain the best predictions of the maximum ER, and the three <i>k</i>-<i>ε</i> models can gain the same CBP value. For a steam ejector with recirculation inside the diffuser, the realizable <i>k</i>-<i>ε</i> model or the enhanced wall treatment is recommended for adoption in the modeling approach. When the spatial discretization scheme of the convection term changes from a second-order upwind scheme to a QUICK scheme, the effect can be ignored for the maximum ER calculation, while only the CBP value from the standard <i>k</i>-<i>ε</i> model with the standard wall function is reduced by 2.13%. The calculation deviation of the ER between the two schemes increases with the back pressure at the unchoked flow region, especially when the standard <i>k</i>-<i>ε</i> model is adopted. The realizable <i>k</i>-<i>ε</i> model with the two wall treatments and the SST <i>k</i>-<i>ω</i> model is recommended, while the standard <i>k</i>-<i>ε</i> is more sensitive to the near-wall treatment and the spatial discretization scheme and is not recommended for an ejector simulation.https://www.mdpi.com/2073-4433/13/1/144steam ejectorturbulence modelnear-wall treatmentsolverspatial discretization |
| spellingShingle | Jingshu Xiao Qiao Wu Lizhou Chen Weichang Ke Cong Wu Xuelong Yang Liangying Yu Haifeng Jiang Assessment of Different CFD Modeling and Solving Approaches for a Supersonic Steam Ejector Simulation Atmosphere steam ejector turbulence model near-wall treatment solver spatial discretization |
| title | Assessment of Different CFD Modeling and Solving Approaches for a Supersonic Steam Ejector Simulation |
| title_full | Assessment of Different CFD Modeling and Solving Approaches for a Supersonic Steam Ejector Simulation |
| title_fullStr | Assessment of Different CFD Modeling and Solving Approaches for a Supersonic Steam Ejector Simulation |
| title_full_unstemmed | Assessment of Different CFD Modeling and Solving Approaches for a Supersonic Steam Ejector Simulation |
| title_short | Assessment of Different CFD Modeling and Solving Approaches for a Supersonic Steam Ejector Simulation |
| title_sort | assessment of different cfd modeling and solving approaches for a supersonic steam ejector simulation |
| topic | steam ejector turbulence model near-wall treatment solver spatial discretization |
| url | https://www.mdpi.com/2073-4433/13/1/144 |
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