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Numerical solutions of the Reynolds-averaged Navier-Stokes equations were obtained with the two-equation K-ϵ turbulence model. Considering the low-Reynolds-number effect in the closed vicinity of a solid boundary, a stream function and vorticity method was developed to consider both the laminar and turbulent stresses throughout the two-dimensional, incompressible flowfield of any arbitrary geometry. At a low Reynolds number (Re = 30), the initially imposed disturbances around an airfoil are damped out; the flow is laminar. At a moderately high Reynolds number (Re = 1000), instability of laminar flow is obtained by exhibiting cyclic patterns in the stream function and vorticity distributions. Nevertheless, only laminar stress occurs in the entire flowfield. At a higher Reynolds number (Re = 106), turbulent stress, which is about three orders of magnitude larger than the laminar stress, occurs at a certain distance downstream of the leading edge and in the wake region.

Computational fluid dynamics simulations of fixed-bed adiabatic adsorption/desorption processes are presented in this paper. Linear driving force model is used for heat and mass transfer rates. A two-dimensional cylindrical canister and three-dimensional automotive production canister geometry are used to study the adsorption/desorption processes of carbon dioxide in helium carrier gas on Norit B4 activated carbon. The two-dimensional results compare well with the results of Hwang et al. [1]. Computational results as breakthrough curve, adsorption amount and temperature profiles are provided. Results show that non-adiabatic model should be used to fully utilize the activated carbon bed capacity prior to breakthrough.

A metal injection molded (MIM) assembly consisting of three parts used in an electric door locking mechanism is presented as an example of what is achievable by the MIM process when Design for Manufacturability (DFM) principles are applied to MIM. The net-shape assembly greatly reduced the labor content over a machined design. The assembly presented considerable challenges for MIM due to the need for high dimensional accuracy (mating parts, sliding fits), geometric tolerances (squareness, flatness, and parallelism), surface finish (for cosmetics and anti-friction), and the complex shape of the components. This paper will show how design optimization, preproduction testing, processing methods, and quality control methods were used to achieve the high process capability requirement. Material selection justification for optimized strength and cost will also be shown.

A computational method was developed for investigating boundary layer control. Solutions of the Reynolds-averaged Navier-Stokes equations were obtained using the two-equation k-∈ turbulence model which includes the low-Reynolds-number effect in the near-wall region. Stream function and vorticity together with the turbulent kinetic energy and its dissipation rate were calculated for the flowfield in a body-fitted coordinate system. By increasing the amount of suction on the upper surface, flow separation could be totally eliminated. Transition from laminar to turbulent flow was delayed. Aerodynamic performance was substantially improved.

Two soot-containing turbulent non-premixed flames burning gaseous acetylene in atmospheric-pressure air were investigated by conducting non-intrusive optical experiments at various flame locations. The differences in burner exit Reynolds numbers of these flames were large enough to examine the influence of flow dynamics on soot formation and evolution processes in heavily-sooting flames. By accounting for the fractal nature of aggregated primary particles (spherules), the proper interpretation of the laser scattering and extinction measurements yielded all the soot parameters of principal interest. With the separation of spherule and aggregate sizes, the axial zones of the prevailing turbulent soot mechanisms were accurately identified. With the high propensity of acetylene fuel to soot, relatively fast particle nucleation process led to high concentrations immediately above the burner exit.

Two dimensional fourth order boundary layer calculations were made for flows over a flat plate with and without flush mounted surface heating. Constant wall temperature, increasing wall temperature and decreasing wall temperature heating cases were studied for different surface heating lengths. The boundary layer properties; temperature, tangential velocity, normal velocity, vorticity and transition location were studied for these temperature distributions. The boundary layer results indicate that with the proper selection of surface temperature variation and length the transition location can be either increased or decreased. Modified boundary layer properties, due to heating are shown to persist well after heating is stopped, even when the flow is turbulent. The results indicate that this technique may be useful in modifying transition and separation locations over airfoils.