Papers by Seyed Mahmood Mousavi
In the present study, the behaviors of Newtonian and shear-thinning non-Newtonian droplets imping... more In the present study, the behaviors of Newtonian and shear-thinning non-Newtonian droplets impinging on heated hydrophilic and hydrophobic surfaces have been investigated numerically using Ansys-Fluent. In this context, the volume-of-fluid technique is applied to track the free-surface of the liquid, and variable time-step is also utilized to control the Courant number. Furthermore, we have considered the dependence of viscosity, density and surface tension on temperature during the simulation. The results are compared to available experimental data at the same conditions, such as boundary conditions. The results demonstrate that there is a good agreement between the obtained results and the experimental trends, concerning normalized diameter profiles at various Weber numbers. Therefore, the focus of the present study is an assessment of the effects of variations in Weber number, contact angle and surface temperature for Newtonian and non-Newtonian liquids on dynamics behavior of droplet in collision with hydrophobic and hydrophilic surfaces. The results represent that the behaviors of Newtonian and non-Newtonian droplets are totally different, indicating the droplet sensitivity to the working parameters.
In the present work, the physics of a three-dimensional shock train in a convergent-divergent noz... more In the present work, the physics of a three-dimensional shock train in a convergent-divergent nozzle is numerically investigated. In this regards, the Ansys-Fluent Software with Algebraic Wall-Modeled Large-Eddy Simulation (WMLES) is used. To estimate precision and errors accumulation we used the Smirinov's method; fine flow structures are obtained via Laplacian of density called shadowgraph and the shock parameter is defined as multiplication of flow Mach number by the normalized pressure gradient, in which shock wave structures are visible distinctly. The results are compared with the experimental data of Weiss et al. [Experiments in Fluids 49(2) (2010) 355–365], in the same conditions including geometry, boundary conditions, etc. The results show that there is good agreement with experimental trends concerning wall pressure and center-line Mach number profiles. Therefore, the focus of the present study is an assessment of various flow control methods to change the shock structures. Consequently, we investigated the effects of passive (bump and cavity) and active (suction and blowing) control methods on the starting point of shock, shock strength, minimum pressure, maximum flow Mach number, etc. All CFD investigations are carried out by High Performance Computing Center (HPCC).
American Journal of Mechanical Engineering, 2013
In the current study, the effect of specific heat ratio, compression ratio, and the maximum to mi... more In the current study, the effect of specific heat ratio, compression ratio, and the maximum to minimum temperature ratio of cycle on the thermal efficiency and the Network of irreversible Diesel cycle have been investigated. For this purpose, numerical solution and multi-objective genetic algorithms with a Pareto optimization method are used to determine the optimum values of specific heat ratio, compression ratio, and the maximum to minimum temperature ratio of cycle. The optimized values of the objective functions (namely Network and thermal efficiency) are then determined by using these vales. The numerical solution shows that the maximum Network and thermal efficiency is obtained simultaneously when the values of specific heat ratio, compression ratio, and the maximum to minimum temperature ratio of cycle are 1.3, 17.7, and 6.0, respectively, and these parameters are obtained by multi-objective genetic algorithms with a Pareto optimization method as 1.3, 17.57, and 6.0. The results obtained from current work are presented in the form of optimal equations for Network thermal efficiency in term of compression efficiency, expansion efficiency and compression ratio of the cycle. The results of current research work can provide a significant insight for optimal design of internal combustion engines including irreversibility.
In the present work, wall modeled large-eddy simulation (WMLES) in the Fluent software is used to... more In the present work, wall modeled large-eddy simulation (WMLES) in the Fluent software is used to investigate the flow physics of a three-dimensional shock–turbulent boundary layer interaction, as an important phenomenon in aerospace science, on a compression–expansion ramp with the angle of 25°. Fine flow structures are obtained via Laplacian of density that called shadowgraph, in which shock wave structures are visible distinctly. The results are compared with the experimental data of Zheltovodov et al., 1990 [33], in the same condition regarding geometry, boundary conditions, etc. as those used by them. Results show that not only there are a good agreement with experimental trends concerning wall pressure, friction coefficient distribution and mean velocity profiles, but also in comparison with those presented by Grilli et al., 2013 [24]. LES simulation, used in this study, presents more accurate results with fewer computational costs. Afterwards, we investigated the influence of discontinuity in wall temperature, varying stagnation pressure and Reynolds number on physics of flow in order to control the shock behavior. Our simulations shows that, discontinuity in wall temperature, varying free stream stagnation pressure and Reynolds number (the free stream Mach number remained essentially constant) influences the starting point of shock, shock strength, separation length and the collision angle of separated and reattachment shock waves.
In the present work, the shock train structure in a convergent-divergent nozzle is in... more In the present work, the shock train structure in a convergent-divergent nozzle is investigated using large eddy simulation (LES) methodology based on different subgrid models, including Smagorinsky-Lilly, Wall-Adapting Local Eddy-Viscosity (WALE) and Algebraic Wall-Modeled LES (WMLES). Therefore, the focus of the present study is to assess various subgrid models in order to predict the location of normal and oblique shocks as well as an extensive numerical study of a shock train system. In this context, dynamic grid adaption techniques and the hybrid initialization in the Fluent software are applied under the three dimensional investigation to
reduce numerical errors and computational cost. The results of different subgrid models are compared with the available experimental data and it is shown that the WMLES produces more accurate results than Smagorinsky-Lilly and WALE models. Thereupon, the shock train behavior is controlled by applying the cooling wall temperature, inlet Mach number and inlet Reynolds number leading to changes in the starting point of shock, shock strength, distance between shocks, minimum pressure and the maximum flow Mach number.
In this paper, in order to investigate the effect of working parameters on 3D non-premixed Flamel... more In this paper, in order to investigate the effect of working parameters on 3D non-premixed Flameless oxidation occurring in the IFRF furnace, large eddy simulation model is applied on
OpenFOAM environment. The radiation and combustion are modeled by applying the finite volume discrete ordinate model and partially stirred reactor, respectively. Furthermore the
detailed mechanism GRI-2.11 is undertaken represent chemistry reactions. The obtained results are compared with the published experimental measurements. After ensuring the accuracy of the LES method, the combustion characteristics are examined with different fuel injection angles, adding H2O, H2, and the inlet Reynolds number. The results indicated significant changes in the characteristics of the Flameless oxidation process.
This paper employs large eddy simulation (LES) to investigate non-premixed flameless oxidati... more This paper employs large eddy simulation (LES) to investigate non-premixed flameless oxidation occurring in the IFRF furnace with varying fuel-injection angle. In order to model radiation and combustion using OpenFOAM software, finite volume discrete ordinate model and partially stirred reactor are applied whereas the detailed
mechanism GRI-2.11 is undertaken represent chemistry reactions. The obtained results are compared with the
experimental measurements of Mancini’s et al. After ensuring the accuracy of the LES method, the combustion
characteristics are examined when using different fuel injection angles into the combustion chamber. The results explain using fuel injection with an angle into the combustion chamber, the net rate of reaction and entropy
generation increases.
This paper discusses the suitability of the Large Eddy Simulation (LES) turbulence modeling for t... more This paper discusses the suitability of the Large Eddy Simulation (LES) turbulence modeling for the accurate simulation of the shock train phenomena in a convergent-divergent nozzle. To
this aim, we selected an experimentally tested geometry and performed LES simulation for the
same geometry. The structure and pressure recovery inside the shock train in the nozzle captured by LES model are compared with the experimental data, analytical expressions and numerical solutions obtained using various alternative turbulence models, includingk–"RNG, k–!SST, and Reynolds stress model (RSM). Comparing with the experimental data, we observed that the LES solution not only predicts the \locations of the ¯rst shock" precisely, but also its results are quite accurate before and after the shock train. After validating the LES
solution, we investigate the effects of the inlet total pressure on the shock train starting point and length. The effects of changes in the back pressure, nozzle inlet angle (NIA) and wall temperature on the behavior of the shock train are investigated by details.
Three-dimensional computational fluid dynamics analyses have been employed to study the compressi... more Three-dimensional computational fluid dynamics analyses have been employed to study the compressible and turbulent flow of the shock train in a convergent–divergent nozzle. The primary goal is to determine the behavior, location, and number of shocks. In this context, full multi-grid initialization, Reynolds stress turbulence model (RSM), and the grid adaption techniques in the Fluent software are utilized under the 3D investigation. The results showed that RSM solution matches with the experimental data suitably. The effects of applying heat generation sources and changing inlet flow total temperature have been investigated. Our simulations showed that changes in the heat generation rate and total temperature of the intake flow influence on the starting point of shock, shock
strength, minimum pressure, as well as the maximum flow Mach number.
In the present work, three dimensional computational fluid dynamics analysis is employed tostudy ... more In the present work, three dimensional computational fluid dynamics analysis is employed tostudy the droplet dynamic behavior of Newtonian and non-Newtonian droplets impinging on a hot surface under various impact conditions. The Navier–Stokes equations for unsteady, incompressible, and viscous fluid flow are solved using a control volume method. The volume-of-fluid (VOF) technique is also used to track the free-surface of the liquid. The effect of viscosity, density and surface tension on droplet dynamic behavior are evaluated considering their dependenceof temperature. The results indicate that the temperature dependence of the both Newtonian and non-Newtonian physicochemical liquid properties must be considered to obtain better agreement of the numerical results with experimental data. After ensuring the accuracy of the numerical methodology, the internal behavior of the droplets is examined, which is shown that the receding velocity of the non-Newtonian droplet is slower than the Newtonian one
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Papers by Seyed Mahmood Mousavi
reduce numerical errors and computational cost. The results of different subgrid models are compared with the available experimental data and it is shown that the WMLES produces more accurate results than Smagorinsky-Lilly and WALE models. Thereupon, the shock train behavior is controlled by applying the cooling wall temperature, inlet Mach number and inlet Reynolds number leading to changes in the starting point of shock, shock strength, distance between shocks, minimum pressure and the maximum flow Mach number.
OpenFOAM environment. The radiation and combustion are modeled by applying the finite volume discrete ordinate model and partially stirred reactor, respectively. Furthermore the
detailed mechanism GRI-2.11 is undertaken represent chemistry reactions. The obtained results are compared with the published experimental measurements. After ensuring the accuracy of the LES method, the combustion characteristics are examined with different fuel injection angles, adding H2O, H2, and the inlet Reynolds number. The results indicated significant changes in the characteristics of the Flameless oxidation process.
mechanism GRI-2.11 is undertaken represent chemistry reactions. The obtained results are compared with the
experimental measurements of Mancini’s et al. After ensuring the accuracy of the LES method, the combustion
characteristics are examined when using different fuel injection angles into the combustion chamber. The results explain using fuel injection with an angle into the combustion chamber, the net rate of reaction and entropy
generation increases.
this aim, we selected an experimentally tested geometry and performed LES simulation for the
same geometry. The structure and pressure recovery inside the shock train in the nozzle captured by LES model are compared with the experimental data, analytical expressions and numerical solutions obtained using various alternative turbulence models, includingk–"RNG, k–!SST, and Reynolds stress model (RSM). Comparing with the experimental data, we observed that the LES solution not only predicts the \locations of the ¯rst shock" precisely, but also its results are quite accurate before and after the shock train. After validating the LES
solution, we investigate the effects of the inlet total pressure on the shock train starting point and length. The effects of changes in the back pressure, nozzle inlet angle (NIA) and wall temperature on the behavior of the shock train are investigated by details.
strength, minimum pressure, as well as the maximum flow Mach number.
reduce numerical errors and computational cost. The results of different subgrid models are compared with the available experimental data and it is shown that the WMLES produces more accurate results than Smagorinsky-Lilly and WALE models. Thereupon, the shock train behavior is controlled by applying the cooling wall temperature, inlet Mach number and inlet Reynolds number leading to changes in the starting point of shock, shock strength, distance between shocks, minimum pressure and the maximum flow Mach number.
OpenFOAM environment. The radiation and combustion are modeled by applying the finite volume discrete ordinate model and partially stirred reactor, respectively. Furthermore the
detailed mechanism GRI-2.11 is undertaken represent chemistry reactions. The obtained results are compared with the published experimental measurements. After ensuring the accuracy of the LES method, the combustion characteristics are examined with different fuel injection angles, adding H2O, H2, and the inlet Reynolds number. The results indicated significant changes in the characteristics of the Flameless oxidation process.
mechanism GRI-2.11 is undertaken represent chemistry reactions. The obtained results are compared with the
experimental measurements of Mancini’s et al. After ensuring the accuracy of the LES method, the combustion
characteristics are examined when using different fuel injection angles into the combustion chamber. The results explain using fuel injection with an angle into the combustion chamber, the net rate of reaction and entropy
generation increases.
this aim, we selected an experimentally tested geometry and performed LES simulation for the
same geometry. The structure and pressure recovery inside the shock train in the nozzle captured by LES model are compared with the experimental data, analytical expressions and numerical solutions obtained using various alternative turbulence models, includingk–"RNG, k–!SST, and Reynolds stress model (RSM). Comparing with the experimental data, we observed that the LES solution not only predicts the \locations of the ¯rst shock" precisely, but also its results are quite accurate before and after the shock train. After validating the LES
solution, we investigate the effects of the inlet total pressure on the shock train starting point and length. The effects of changes in the back pressure, nozzle inlet angle (NIA) and wall temperature on the behavior of the shock train are investigated by details.
strength, minimum pressure, as well as the maximum flow Mach number.