Peristaltic Flow with Heat Transfer on Sisko Fluid in a Ciliated Arteries
Bothaina Mohamed Agoor,
Mohamed Eissa Sayed-Ahmed,
Heba Alam
Issue:
Volume 6, Issue 3, September 2020
Pages:
70-78
Received:
30 June 2020
Accepted:
24 July 2020
Published:
10 August 2020
Abstract: The flow of blood through arteries is an important physiological problem. In the present investigation, we carried out to study the peristaltic of non-Newtonian incompressible blood flow with heat transfer through ciliated arteries. The blood flow is characterized by the generalized Sisko model. The nonlinear partial differential equations of the problem are simplified by using an approximation of long wavelength and low Reynolds number. The differential equations are solved analytically by using the perturbation method. We find that Sisko fluid parameter and the power index effects the behavior of the velocity where the velocity increase in the arteries then decreases near the wall, but the Sisko parameter give opposite behavior where the velocity decrease then increases near the wall of arteries. The velocity increase in arteries with the increase of cilia length and elliptic path. The temperature profile increases then decreases near the wall of arteries with the increase of power index, Sisko fluid parameter and Grashof number, while the temperature decrease then increase near the wall with increase of Sisko parameter. The effect of increase in the cilia length give an increase of the temperature. The pressure gradient increases with the increase of power index and elliptic path, while the pressure gradient decrease with an increase of elliptic path, Sisko parameter. The pressure gradient increases and decreases in a different interval with the increase the cilia length. Our results are illustrated through a set of Figures.
Abstract: The flow of blood through arteries is an important physiological problem. In the present investigation, we carried out to study the peristaltic of non-Newtonian incompressible blood flow with heat transfer through ciliated arteries. The blood flow is characterized by the generalized Sisko model. The nonlinear partial differential equations of the p...
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Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance
Nekkanti Sitaram,
Vanamala Ushasri
Issue:
Volume 6, Issue 3, September 2020
Pages:
79-88
Received:
18 May 2020
Accepted:
13 July 2020
Published:
13 August 2020
Abstract: The objective of the present investigation is to examine the possibility of performance improvement, improvement of the exit flow uniformity and desensitization of the tip clearance effects on the performance of a low speed centrifugal impeller. Computational investigations using a commercial CFD software are undertaken. Six configurations of blade tips are investigated. They are square tip (Basic), tip chamfered on pressure surface (P1 and P2), tip chamfered on suction surface (P1 and P2) and tip chamfered on pressure and suction surfaces (PS1). Computations are carried out with optimized multiblock grids for these six configurations at five flow coefficients, namely 0.28 and 0.34 (below design flow coefficient), 0.42 (design flow coefficient) and 0.48 and 0.52 (above design flow coefficient) and at three values of tip clearance, viz., 1% (small value), 2% (nominal value) and 5% (large value) of the blade exit height. From the investigations, it is found that the impeller with the chamfer on suction surface shows small improvement in performance. In addition this configuration has minimum tip clearance sensitivity. A decrease in the chamfer on suction surface further may improve the impeller performance. A maximum percentage of 0.18% improvement in the total pressure coefficient is obtained at 5% tip clearance and a flow coefficient of 0.52 for configuration S2. However chamfer on the pressure surface deteriorates the impeller performance.
Abstract: The objective of the present investigation is to examine the possibility of performance improvement, improvement of the exit flow uniformity and desensitization of the tip clearance effects on the performance of a low speed centrifugal impeller. Computational investigations using a commercial CFD software are undertaken. Six configurations of blade...
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A Novel Viscous Throughflow Model for Compressor Analysis and Its Application
Hailiang Jin,
Daobin Qiu,
Yueqian Yin
Issue:
Volume 6, Issue 3, September 2020
Pages:
89-94
Received:
12 July 2020
Accepted:
25 August 2020
Published:
7 September 2020
Abstract: Throughflow calculations are still an inevitable step in the aerodynamic design of compressors. The viscous throughflow model derived from Navier-Stokes equations can be more capable in predicting choked flow and capturing shock waves compared to the traditional methods. In this paper, authors further developed the inviscid model for a previously developed throughflow analysis method. To obtain the governing equations, three-dimensional Navier-Stokes equations combined with the Spalart-Allmaras turbulence model were circumferentially averaged with the assumption that the flow was circumferentially uniform. A viscous blade force and an inviscid blade force had been calculated. The Miller's correlations of deviation angle and loss were incorporated to model these forces. The governing equations are discretized by an explicit four-step Runge-Kutta scheme and solved by a time-marching finite volume method. Current model was verified through predicting the performances of a 1.5 stage fan. The agreements between the experiments and calculations are reasonably good. This throughflow model can predict quite similar flow patterns and radial profiles of some parameters compared to a CFD software, which shows the potential of this model. There are still some notable deviations between the results from throughflow analysis and that from CFD calculation. Future work is to improve the prediction of deviation angle and loss near the endwall regions.
Abstract: Throughflow calculations are still an inevitable step in the aerodynamic design of compressors. The viscous throughflow model derived from Navier-Stokes equations can be more capable in predicting choked flow and capturing shock waves compared to the traditional methods. In this paper, authors further developed the inviscid model for a previously d...
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