Investigation of the Motive Steam Pressure Effect on Performance and Reverse Flows in Sugar Factory Thermo-compressor: Validation and Numerical Study

IntroductionThermo-compressors or ejectors are used to enhance the vapor enthalpy in the process industry. The low costs of construction and maintenance, and simple structure, have increased by using this equipment in relevant fields of industry and agriculture. The thermo-compressor's inlet parameters, including the thermodynamic properties of the motive steam and suction vapor, are the foremost affecting factor of a thermo-compressor.The steam used in processing factories loses its capability after passing through evaporators due to the reduction of pressure and temperature, gets cooled again, and returns to the boiler despite having a moderate energy level. Therefore, the use of vapor-recovery equipment can increase the efficiency of energy systems. That will lead to a significant reduction in greenhouse gas emissions and harmful environmental effects, which increase the lifetime of energy resources.Materials and MethodsThe realizable k-ε turbulence model is used to simulate turbulence within the flow. The thermo-compressor geometry has meshed in 2D and 3D modes to apply the conservation laws. For this purpose, quadratic (quad) and hexahedral (hex) types are used for two and three-dimensional meshing, respectively. Structured meshes have a high ability to obtain numerical results due to creation of structural meshes in the flow direction.The axisymmetric structure of the thermo-compressor leads to a half simulation of geometry. The thermodynamic properties of the input flows and their variations in the output, such as pressure, velocity, Mach number, and mass ratios for different motive steam pressure are extracted and discussed.Results and DiscussionDifferent levels of meshes are examined to investigate the mesh-independence test. In axisymmetric two-dimensional analysis, these levels include 33460, 51340, 78620, and 103590 cells, respectively. The relatively insignificant difference in motive flow for the third and fourth mesh levels (which proves less than 5%) clearly shows the independence of the results from the mesh size. Regarding the time considerations, the grid with 78,620 meshes was used in the simulations.The experimental data from the article by Sriveerakul et al. (2007) are used to validate the numerical results of the present work. Validation shows that the results obtained from the simulations are in good agreement with the experimental data. Since the final results of the two-dimensional analysis are very close to the three-dimensional