Chien-Hsin Chen

Bio: Chien-Hsin Chen is an academic researcher. The author has contributed to research in topics: Newtonian fluid & Heat transfer coefficient. The author has an hindex of 1, co-authored 1 publications receiving 120 citations.

Heat transfer in a power-law fluid film over a unsteady stretching sheet

Abstract: In this paper the problem of momentum and heat transfer in a thin liquid film of power-law fluid on an unsteady stretching surface has been studied. Numerical solutions are obtained for some representative values of the unsteadiness parameter S and the power-law index n for a wide range of the generalized Prandtl number, 0.001 ≤ Pr ≤ 1000. Typical temperature and velocity profiles, the dimensionless film thickness, free-surface temperature, and the surface heat fluxes are presented at selected controlling parameters. The results show that increasing the value of n tends to increase the boundary-layer thickness and broadens the temperature distributions. The free-surface temperature of a shear thinning fluid is larger than that of a Newtonian fluid, but the opposite trend is true for a shear thickening fluid. For small generalized Prandtl numbers, the surface heat flux increases with a decrease in n, but the impacts of n on the heat transfer diminish for Pr greater than a moderate value (approximately 1 ≤ Pr ≤ 10, depending on the magnitude of S).

Analytic solutions for a liquid film on an unsteady stretching surface

Abstract: The momentum and heat transfer in a laminar liquid film on a horizontal stretching sheet is analyzed by the Homotopy analysis method (HAM). Analytic series solutions are given and compared with numerical results given by other authors. The good agreement between them shows the effectiveness of HAM to the problem of liquid film on an unsteady stretching surface.

Analysis of the flow of a power-law fluid film on an unsteady stretching surface by means of homotopy analysis method

Abstract: Flow of a power-law fluid film on an unsteady stretching surface is analyzed by means of homotopy analysis method (HAM [1] ). For real power-law index and the unsteadiness parameter in wide ranges, analytic series solutions are given and compared with the numerical results. The good agreement between them shows the effectiveness of HAM to this problem. Additionally, unlike previous studies, the value of the critical unsteadiness parameter S 0 , above which no solution exists, is determined analytically in this paper.

Effect of viscous dissipation on heat transfer in a non-Newtonian liquid film over an unsteady stretching sheet

Abstract: Convective heat transfer of non-Newtonian fluids within a thin liquid film on an unsteady stretching sheet is investigated, taking into consideration the viscous dissipation effect. Results for the temperature distribution, the free-surface temperature, and the wall temperature gradient are illustrated at selected values of the unsteadiness parameter, the power-law index, and Eckert number for a wide range of the generalized Prandtl number, ranging from 0.001 to 1000. Also, new results for the velocity profiles, the free-surface velocity, and the wall shear stress are presented. The deviation from Newtonian behavior on the variation of the horizontal velocity component across the liquid film is observed more significant than that reported in the previous investigation. As compared to the case where viscous dissipation is neglected, the dimensionless fluid temperature is found to increase when the fluid is being heated but to decrease when the fluid is being cooled. For the fluid heating case, the dimensionless fluid temperature decreases monotonically in the vertical direction; while for the fluid cooling case it decreases rapidly at first, reaches a minimum value, and then increases more gradually to its free-surface value. The wall temperature gradient takes a higher value for a negative Eckert number but a lower value for a positive Eckert number, as compared to the case without viscous dissipation. The effects of positive or negative Eckert numbers on heat transfer are found to be more pronounced for higher generalized Prandtl numbers.