Beneficial design of unbaffled shell-and-tube heat exchangers for attachment of longitudinal fins with trapezoidal profile

A parametric variation followed with Kern’s method of design of extended surface heat exchanger has been made for an unbaffled shell-and-tube heat exchanger problem. For this analysis, the rectangular and trapezoidal fin shapes longitudinally attached to the fin tubes are taken. In comparison with the attachment of trapezoidal fins, it is found that the heat transfer rate was lesser than the rectangular cross section by keeping a constant outer diameter of the shell along with all other constraints of a heat exchanger design, namely, number of passes, tube outer diameter, tube pitch layout, etc. But when the total volume of the fin over a tube was kept constraint, using trapezoidal fins the heat transfer rate is found to be increased and consequently the pressure drop decreases much more than in the case of fins with rectangular cross section. This optimization has shown beneficial results in all the cases of different constraints of heat exchanger design analysis

Biochemical and bioenergetic aspects of denitrification in `Rhodopseudomonas sphaeroides` forma sp. `denitrificans` / by Balaram Kundu

Offprints of author's articles insertedBibliography: leaves 180-194xxv, 194 leaves : ill ; 30 cm.Thesis (Ph.D.) -- University of Adelaide, Dept. of Agricultural Biochemistry, 198

Review and Analysis of Electro-Magnetohydrodynamic Flow and Heat Transport in Microchannels

This paper aims to develop a review of the electrokinetic flow in microchannels. Thermal characteristics of electrokinetic phenomena in microchannels based on the Poisson–Boltzmann equation are presented rigorously by considering the Debye–Hückel approximation at a low zeta potential. Several researchers developed new mathematical models for high electrical potential with the electrical double layer (EDL). A literature survey was conducted to determine the velocity, temperature, Nusselt number, and volumetric flow rate by several analytical, numerical, and combinations along with different parameters. The momentum and energy equations govern these parameters with the influences of electric, magnetic, or both fields at various preconditions. The primary focus of this study is to summarize the literature rigorously on outcomes of electrokinetically driven flow in microchannels from the beginning to the present. The possible future scope of work highlights developing new mathematical analyses. This study also discusses the heat transport behavior of the electroosmotically driven flow in microchannels in view of no-slip, first-order slip, and second-order slip at the boundaries for the velocity distribution and no-jump, first-order thermal-slip, and second-order thermal-slip for the thermal response under maintaining a uniform wall-heat flux. Appropriate conditions are conferred elaborately to determine the velocity, temperature, and heat transport in the microchannel flow with the imposition of the pressure, electric, and magnetic forces. The effects of heat transfer on viscous dissipation, Joule heating, and thermal radiation envisage an advanced study for the fluid flow in microchannels. Finally, analytical steps highlighting different design aspects would help better understand the microchannel flow’s essential fundamentals in a single document. They enhance the knowledge of forthcoming developmental issues to promote the needed study area

A new method for non-Fourier thermal response in a single layer skin tissue

The non-Fourier and Fourier thermal responses in one-dimensional single layer skin tissue under selective boundary conditions are investigated by applying the Laplace Transformation method (LTM). The present method accurately describes the deviation of the temperature response of the non-Fourier model from the Fourier model and roles of important physiological parameters. A systematic exact analytical study on the discrepancies between the thermal wave model and the Pennes' bioheat model shows that the present method is an alternate reliable technique to describe the complicated bioheat problems under different boundary conditions. Three cases, namely constant skin temperature, constant and variable heat flux conditions at the skin surface have been taken to determine the tissue temperature whereas an insulated condition at the core has always been satisfied. From the result, it can be highlighted that cosine heat flux at the skin surface amplifies non-Fourier's response of temperature as well

Thermal Analysis of Porous Pin Fin used for Electronic Cooling

AbstractThe present work investigates the temperature distribution, performance parameters and heat transfer rate through a porous pin fin in natural convection condition. This study is based on finite-length fin with insulated tip. To formulate the heat transfer equation for the porous fin, the energy balance and Darcy's model are used. An analytical technique called Adomian decomposition method (ADM) is proposed for the solution methodology. To validate the analytical results, a numeric scheme, namely, finite difference method is adopted. The results indicate that the numerical data and analytical approach are in agreement with each other. The effects of various geometric and thermophysical parameters on the dimensionless temperature distribution and fin performance are studied that may help in optimum design analysis of a porous pin fin. Finally, the increase in heat transfer is noticed by selecting porous medium condition in the fin