Unsteady prediction of cavitating flow around a three dimensional hydrofoil by using a modified RNG k-ε model

Ahn, Soo-Hwang; Xiao, Yexiang; Wang, Zhengwei; Luo, Yongyao; Fan, Honggang

doi:10.1016/j.oceaneng.2018.04.005

Cited by 34 publications

(14 citation statements)

References 26 publications

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“…51 Details of the RNG k – ε turbulence model can be found in Ahn et al. 49 and Patil et al. 50 In the present configuration (Figure 5(a)), the green rectangular inlets are defined as velocity inlet boundaries.…”

Section: Numerical Setupmentioning

confidence: 99%

“…Note that equation (10) can represent the continuity, momentum, energy and concentration equations by assigning different values to the dummy variable, ϕ. Additionally, the re-normalization group (RNG) k – ε turbulent model, 49,50 as shown in equations (11) and (12), was adopted to close the RANS equations. where k is the turbulent kinetic energy, ε is the turbulent dissipation rate, G k represents the generation of turbulence kinetic energy caused by the mean–velocity gradients, G b is the generation of turbulence kinetic energy caused by buoyancy and Y M represents the contribution of the fluctuating dilatation in compressible turbulence to the overall dissipation rate.…”

Section: Numerical Setupmentioning

confidence: 99%

See 1 more Smart Citation

Implementing an emissions-rate model in computational fluid dynamics simulations of contaminant diffusion processes: A case study with xylene in painting workshops

Liu

Huang

Yuan³

et al. 2020

Indoor and Built Environment

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Organic solvents frequently lead to substantial occupational health issues in secondary industries. This study examined the xylene diffusion process in painting workshops as a case study to develop a control of indoor air quality in manufacturing workshops. Three-dimensional simulations of xylene emission were built based on a ventilated chamber test to provide the source term for the mathematical model. An exponential relationship was established between xylene emissions rates and time. Numerical results obtained using the emissions rate model were more consistent with experimental data than those from constant emission rate. Owing to the property that is denser than air; therefore, given the coupled influence of molecular diffusion, gravity and environmental turbulence, the xylene concentration at a height of 0.75–2.5 m is high, and it could possibly exceed the Chinese standard, GBZ 2.1–2019 permissible concentration time weighted average (PC-TWA) of 50 mg/m3 in human-occupied zones. At the height of the human breathing zone (1.1 m), the aggregated concentration may even exceed the PC-TWA at 450 s by 100 times. Considering that the diffusion of xylene in a painting workshop represents heavy-gas pollutant diffusion problems, this study can be extended to predict pollutant concentration distributions in other secondary industrial workshops.

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Section: Numerical Setupmentioning

confidence: 99%

Section: Numerical Setupmentioning

confidence: 99%

Implementing an emissions-rate model in computational fluid dynamics simulations of contaminant diffusion processes: A case study with xylene in painting workshops

Liu

Huang

Yuan³

et al. 2020

Indoor and Built Environment

View full text Add to dashboard Cite

show abstract

“…The RNG kÀe model adopts a statistical technique called renormalization grouping to correct for the turbulence viscosity by considering the condition of rotation and swirl, and it has a better analysis ability in the internal flow field calculation process for axial-flow pump devices. 35 Based on the experimental results and the characteristics of the three turbulence models, and combined with the research content of this paper, the RNG kÀe model was adopted.…”

Section: Governing Equations and Turbulence Modelsmentioning

confidence: 99%

Analysis of inlet flow passage conditions and their influence on the performance of an axial-flow pump

Zhang

Shi

Tang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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The inlet flow conditions will directly affect impeller performance, which is of great concern to pump designers. In this study, based on two axial-flow pump devices, the influence of the evaluation criteria of inlet flow conditions and numerical grid scales on the accuracy of the simulation are investigated, the correctness of the numerical simulation are verified by experiments. The axial velocity distribution uniformity, axial velocity weighted average angle and hydraulic loss are calculated with three grid scales commonly used in engineering. The applicability of three turbulence models in engineering is verified. The influence of the uniformity of the axial velocity distribution on the impeller is quantitatively explored by installing a group of vortex generators. The results show that the simulation errors of the common formula of the axial velocity distribution uniformity for the elbow inlet passage and front-shaft tubular inlet passage are 16.3% and 14.6%, respectively; the modified formula limited the computational error to 0.2%, which reduced the axial velocity distribution uniformity dependence on the grid. The quantitative relationship between inlet flow conditions and pump performance was established, as the impeller efficiency decreased linearly with decreasing axial velocity distribution uniformity.

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“…The basic equations of fluid mechanics are mainly composed of the continuity equation, the motion equation and the energy equation. The standard k − ε turbulence equations 22 are shown in Formulas (1) and (2).…”

Section: Mathematical Modelingmentioning

confidence: 99%

Numerical calculation and experimental study on response characteristics of pneumatic solenoid valves

Zhang

Lü

et al. 2019

Measurement and Control

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In order to analyze the response characteristics of the solenoid valve in depth, the flow field of the solenoid valve is analyzed by means of the computational fluid dynamics, and the aerodynamic parameters that are difficult to be obtained by the traditional methods are obtained with software FLUENT. We also set up the mathematical model of the solenoid valve, including the aerodynamic model, the circuit model, the magnetic circuit model and the mechanical motion model. The calculation is completed in the Simulink, and the results of the calculation are analyzed. A set of the solenoid valve response characteristic test system is built, and the response characteristic parameters such as response time and maximum action frequency of the solenoid valve are tested. The experimental results are verified by comparing them with the simulation results. The final result shows that the response characteristics are basically irrelevant to the action frequency at a suitable working frequency. The open switching time of the solenoid valve decreases with the increase in the inlet pressure and the driving voltage and increases with the increase in the number of coil turns. The close switching time increases with the increase in the inlet pressure, the driving voltage and the number of coil turns.

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Unsteady prediction of cavitating flow around a three dimensional hydrofoil by using a modified RNG k-ε model

Cited by 34 publications

References 26 publications

Implementing an emissions-rate model in computational fluid dynamics simulations of contaminant diffusion processes: A case study with xylene in painting workshops

Implementing an emissions-rate model in computational fluid dynamics simulations of contaminant diffusion processes: A case study with xylene in painting workshops

Analysis of inlet flow passage conditions and their influence on the performance of an axial-flow pump

Numerical calculation and experimental study on response characteristics of pneumatic solenoid valves

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