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Fluid Flow Characteristics (fluid + flow_characteristic)
Selected AbstractsHeat and fluid flow characteristics inside differentially heated square enclosures with single and multiple sliding wallsHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 7 2009E.M. Wahba Abstract Fluid flow and heat transfer characteristics of differentially heated lid driven cavities are numerically modeled and analyzed in the present study. One-, two-, and four-sided lid driven cavity configurations are considered with the vertical walls being maintained at different temperatures and the horizontal walls being thermally insulated. Eight different cavity configurations are considered depending on the direction of wall motion. The Prandtl number Pr is taken to be 0.7, the Grashof number is taken to be 104, while two values for the Richardson number Ri are considered, 0.1 and 10. It is found that both the Richardson number and the cavity configuration affect the heat and fluid flow characteristics in the cavity. It is concluded that for Ri=0.1, a four-sided driven cavity configuration with all walls rotating in the same direction would triple the value of the average Nusselt number at the cold wall when compared to a one-sided driven cavity configuration. However, for Ri=10, the cavity configuration has minimal effect and all eight cases result in an average Nusselt number value at the cold wall ranging between 1.3 and 1.9. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/htj.20264 [source] Heat transfer and fluid flow characteristics in a swirling impinging jetHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 5 2005Mamoru Senda Abstract An experimental study on heat transfer and fluid flow has been carried out for a swirling round impinging jet. A thermosensitive liquid crystal sheet was used for the heat transfer measurements and the three velocity components were measured with LDV in the stagnation region for cases where the Swirl number Sw = 0.0, 0.22, and 0.45 at the Reynolds number Re = 8100. The formation of recirculation flow due to a swirl near the impinging wall was found to deteriorate the heat transfer coefficient in the stagnation region and results in a more uniform distribution of the Nusselt number with an increasing Swirl number. The heat transfer mechanism of the swirling impinging jet is discussed based on the flow characteristics of the mean velocities and turbulence quantities. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(5): 324,335, 2005; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/htj.20068 [source] Continuous Flow Radio Frequency Heating of Water and Carboxymethylcellulose SolutionsJOURNAL OF FOOD SCIENCE, Issue 1 2003Q. Zhong ABSTRACT Tap water and 1% CMC solutions were heated in a 40.68 MHz, 30 kW continuous flow radio frequency unit. Temperatures at different vertical and radial locations were monitored by fiber optic probes during batch heating of tap water and 1% CMC solution. Temperatures at different locations were similar during batch heating of tap water, while a significant temperature difference was observed for 1% CMC solutions, with the temperature close to the wall being higher than that at the center. Similar trends were observed during continuous heating of tap water and 1% CMC solutions, with Twall > TR/2 > Tcenter for the latter. The observations were a result of different dielectric properties of these 2 fluids, as well as the fluid flow characteristics during continuous heating. [source] Analysis of stirred tanks with two-zone modelsAICHE JOURNAL, Issue 10 2009Ville Alopaeus Abstract Stirred tank turbulence and fluid flow characteristics are analyzed based on a two-zone model. Instead of using the zonal model for stirred tank performance prediction as often proposed in the literature, the zoning is used here as a tool for mixing analysis. A systematic zoning approach is proposed, where the tank is divided into two nested regions. By gradually increasing the inner zone volume, continuous curves can be obtained for turbulent energy dissipation distribution and pumping numbers between the zones as functions of the zone sizes. It is shown here that these curves can be used as a powerful tool for visualizing stirred tank performance. They can be used, e.g., in impeller performance comparisons and analysis of mixing characteristics with changing rheology, or to examine various numerical aspects related to stirred tank CFD modeling. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Numerical Analysis of Isothermal Gaseous Flows in MicrochannelCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2006B. Cao Abstract Two-dimensional compressible momentum equations were solved by a perturbation analysis and the PISO algorithm to investigate the effects of compressibility and rarefaction on the local flow resistance of isothermal gas flow in circular microchannels. The computations were performed for a wide range of Reynolds numbers and inlet Mach numbers. The explicit expression of the normalized local Fanning friction factor along the microchannel was derived in the present paper. The results reveal that the local Fanning friction factor is a function of the inlet Mach number, the Reynolds number and the length-diameter ratio of the channel. For larger Reynolds and inlet Mach numbers, the friction coefficient in the microchannel is higher than the value in a macrotube, and the gas flow in the microchannel is dominated only by compressibility. For smaller Reynolds and inlet Mach numbers, the Fanning friction factor of gas flow in the microchannel is lower than that in a circular tube of conventional size due to slip flow at the wall and thus, rarefaction has a significant effect on the fluid flow characteristics in a microchannel. [source] | ||||||||||