Mohammad Moshfeghi
Sogang University
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Publication
Featured researches published by Mohammad Moshfeghi.
Volume 1B, Symposia: Fluid Machinery; Fluid-Structure Interaction and Flow-Induced Noise in Industrial Applications; Flow Applications in Aerospace; Flow Manipulation and Active Control: Theory, Experiments and Implementation; Multiscale Methods for Multiphase Flow; Noninvasive Measurements in Single and Multiphase Flows | 2014
Mohammad Moshfeghi; Nahmkeon Hur
Synthetic jet actuators (SJA) have shown their efficiency in manipulating the aerodynamic forces on airfoils and blades. Generally, the injection angle is assumed to be an important factor for the injection-based flow control techniques, especially in moderate separation. However, it is important to know the level of effectiveness and the aerodynamic mechanism through which a SJA may affect an airfoil at a high angle of attack. The present research studies the effects of angle between the injected flow and the surface’s tangent line (Coanda effect) over the S809 airfoil equipped with a SJA, using detached eddy simulation (DES). The airfoil is assumed to be at an angle of attack of 25°. Three different cases with jet flow angles of 5°, 15° and 25° are simulated at a constant momentum coefficient of 4.5×10−3. The SJA frequency is 125 Hz for all cases and the simulations are conducted at the Reynolds number of one million. The effects of the jet angle on the streamline, pressure distribution and lifts and drag values are investigated.Copyright
VII European Congress on Computational Methods in Applied Sciences and Engineering | 2016
Shinhwa Choi; Nahmkeon Hur; Mohammad Moshfeghi; Seongwon Kang; Wonjung Kim
Using cardiopulmonary circulatory assist devices has been increased in the recent years as more models are available in the market. These devices can be employed in the situation during which both cardiac and respiratory support to a patient’s heart and lungs have to be provided, either during or after surgeries, for short time or even in the case of severe disease, for a period of weeks. Hence, it is critical to know the details of the phenomena happen inside a blood pump from both mechanical performances (such as pressure head and mechanical efficiency) and biomedical factors (such as hemolysis and thrombosis) and to design an optimum pump from both aspects. This paper investigates development of centrifugal blood pump impeller, specifically with focusing on the performances during ECMO condition. The baseline model is designed by investigating existing commercial pumps and considering results of recirculation, pressure heads and mechanical efficiencies together with their biomechanical performance via Modified Indices of Hemolysis (MIH). Afterword, two more modified models are designed and simulated. Overall, a comprehensive comparison between the results of all three case demonstrate that when impeller radius and prime volume is smaller, recirculation is reduced at impeller and MIH value becomes lower. Additionally, high scalar shear stress is observed near the volute and impeller walls and inside the top cavity gap.
ASME 2015 International Mechanical Engineering Congress and Exposition | 2015
Minwook Chang; Nahmkeon Hur; Mohammad Moshfeghi; Seongwon Kang; Wonjung Kim; Shin Hyoung Kang
Centrifugal blood pumps have to be considered from both mechanical and biomechanical aspects. While, evaluations of mechanical factors, such as performance curve, are straightforward, biomechanical parameters, such as hemolysis indices, are still indistinct. Hence, different mathematical models and computational methods have been employed for the evaluation of hemolysis indices. This article aims to investigate four different types of centrifugal blood pumps from both mechanical and biomechanical aspects. The pumps are cone-type impeller (Type-A), channel-type impeller with shroud (Type-B), open impeller without shroud (Type-C) and shrouded impeller-type (Type-D). The CFD simulations are conducted using standard k-e turbulence model in multiple reference frame (MRF) method. Various values for rotational speed and flow rate are studied. The streamlines clearly show the effects of impeller geometry on flow patterns. It is also demonstrated that in all of the models, the areas of the recirculation have high value of von Mises stress. In addition, the effect of the volute in the Type-D on the pressure distribution and streamline smoothness is clearly observed. In another part, the modified index of hemolysis (MIH) calculated based on Eulerian approach is investigated for three predefined conditions of extracorporeal membrane oxygenation (ECMO), ventricular assist device (VAD), and full-load. The results reveal that the Type-A and Type-D have the highest and lowest MIH values, respectively in all of the predefined conditions. In addition, all of the pumps generate lower amount of hemolysis when they are operated in VAD condition.Copyright
Applied Thermal Engineering | 2014
Junghyun Lee; Mohammad Moshfeghi; Y.K. Choi; Nahmkeon Hur
Journal of Mechanical Science and Technology | 2015
Mohammad Moshfeghi; Nahmkeon Hur
Journal of Mechanical Science and Technology | 2017
Mohammad Moshfeghi; Nahmkeon Hur
Computers & Fluids | 2016
Nahmkeon Hur; Mohammad Moshfeghi; Wonju Lee
대한기계학회 춘추학술대회 | 2013
Mohammad Moshfeghi; Nahmkeon Hur
Journal of Mechanical Science and Technology | 2017
Nahmkeon Hur; M. Kwak; Mohammad Moshfeghi; C.-S. Chang; N.-W. Kang
Volume 1B, Symposia: Fluid Mechanics (Fundamental Issues and Perspectives; Industrial and Environmental Applications); Multiphase Flow and Systems (Multiscale Methods; Noninvasive Measurements; Numerical Methods; Heat Transfer; Performance); Transport Phenomena (Clean Energy; Mixing; Manufacturing and Materials Processing); Turbulent Flows — Issues and Perspectives; Algorithms and Applications for High Performance CFD Computation; Fluid Power; Fluid Dynamics of Wind Energy; Marine Hydrodynamics | 2016
Mohammad Moshfeghi; Iman Rahimipetroudi; Nahmkeon Hur