Heat Transfer in Non-Newtonian Fluid Flow from an Oblique Array of Plates of Unequal Length

The periodically fully developed laminar heat transfer and pressure drop of arrays with non-uniform plate length aligned at angle to the flow direction of Non-Newtonian and Newtonian fluids are studied by numerical analysis. The body-fitted coordinate system is adopted to retain the corresponding periodic relation of the lines in physical coordinate system and computational domains in body-fitted coordinate system. The computations are carried out in one periodic cycle.Power law model non-Newtonian fluids are considered. The continuity equation, the x-y momentum equations, and the energy equation with viscous energy dissipation are presented. The power law scheme, discretization, SIMPLE algorithm, TDMA, Jacobi iterative methods are adopted in the numerical procedure for the integration of the governing equations.In this dissertation, focus is placed on the effects of the flow index, the generalized Reynolds number, and various geometrical parameters on the flow field and thermal behavior of the flow.The results are obtained and show that the form drag of plate including the inlet and outlet effects gradually becomes significant after a certain value of Reynolds number.The flow re-circulation has a significant influence on the average heat transfer at higher Reynolds number. The increment of flow index leads to the increase of friction factor but decrease of heat transfer and fluid temperature.The longer plate causes the increase of the friction factor and heat transfer as well as fluid temperature. The increment of transverse pitch leads to the decrease of both friction factor and heat transfer as well as fluid temperature.The increment of plate angle leads to the increase of friction factor, average heat transfer, and fluid temperature

LAMINAR HEAT TRANSFER IN NON-NEWTONIAN PLANE POISEUILLE-COUETTE FLOW

長崎大学学位論文 学位記番号:博（生）甲第20号 学位授与年月日:平成16年3月31

Semi-analytical approach-based studies of the squeeze film lubrication between rough porous annular discs: Rabinowitsch fluid model

In recent years, there has been much interest in the effects of porosity and surface roughness (SR) or geometric irregularities between two moving plates under hydrodynamic lubrication. Porous bearings are used extensively in wide range of equipment, including computers, office equipment, home appliances, electric motors, and vehicles. In light of the importance of the aforementioned applications, we explored how SR and porous materials affect annular discs under the condition of a squeeze film. A five-point Gauss quadrature integral formula has been used to examine the characteristics of annular discs and a small perturbation method has been used to discretise the governing Rabinowitsch fluid flow (RFF) equations. The impact of nonlinear parameters on the behaviour of porosity and SR have been visualised in terms of film pressure (FP), load carrying capacity (LCC), and squeeze response time (SRT) of annular discs. Under the conditions of pseudoplastic and dilatant fluids, the effects of SR and porous materials between annular discs have been estimated in the form of the film pressure, LCC, and SRT and are presented in this manuscript as tables and graphs. According to the findings, the performance of an annular disc is significantly affected by porous material and radial roughness patterns. In addition, when RFF is carried through a rough surface and porous media, the performance is found to improve for dilatant fluids but suffer for pseudoplastic fluids

Study of rheological behaviour of polymer melt in micro injection moulding with a miniaturized parallel plate rheometer

Abstract The study of the rheological behaviour of the polymer in micro cavities is one of the aspects related to the technology of micro injection moulding (μIM) still substantially unresolved. Even today, there are no databases on the rheological characteristics of the material specific for the μIM, which, therefore, takes into account a number of important differences compared to the conventional injection moulding. In this paper, the study of the rheological behaviour of the polymer melt in a thin plate cavity with variable thickness has been conducted. The use of a micro injection moulding machine, on which the prototype of a sensorized mould with pressure and temperature sensor has been mounted, allowed the rheological study of the material under high shear rate conditions. After preliminary tests on different thicknesses, it has been studied the viscosity of polymer melt for 400 μm thickness. The viscosity reduction observed meets the characteristics of a pseudoplastic fluid subject to shear thinning and the wall slip seems to play an important role in the apparent reduction of viscosity. The results suggest to increase injection speed, and consequently injection pressures, so that the reduced viscosity can help melt flow to overcome the extreme conditions due to the aspect ratio and to obtain greater efficiency from the filling phase against the high cooling rate typical of micro injection moulding.

粘性逸散と軸方向熱伝導を考慮した環状流路内の層流熱伝達

長崎大学学位論文 学位記番号:博（生）甲第59号 学位授与年月日:平成17年3月18

Numerical representations of fluid mixing

The work contained within this thesis is concerned with a theoretical investigatiop of both laminar and thermally driven types of cavity flow, together with an analysis of their associated mixing processes which find applications to Industrial mixing and also to the environment. The mixing efficiency has been viewed from two perspectives namely the tracking of a selection of fluid particles, and also the simulation of the dispersive mixing of a coloured fluid element as carried along by the flow. This thesis also incorporates features of both Newtonian and a wide range of non-Newtonian fluids