An introduction to heat transfer

Introduction to heat transfer

Fluid phase equilibria

Publisher Summary Impinging liquid jets have been demonstrated to be an effective means of providing high heat or mass transfer rates in industrial transport processes. This chapter summarizes the available analytical and experimental work in the area with the objective of correlating the research findings. Significant progress has been made in understanding the fundamentals of heat, mass, and momentum transport in these systems. This chapter suggests that, there is considerable need for further research in liquid jet array applications, both in submerged and free-surface jet configurations. Cross-flow effects in these systems, which have been quite well characterized for submerged jets, have received only superficial treatment for free-surface jets. The physical phenomena are highly complex, requiring careful experimental investigation.

Single-Phase Liquid Jet Impingement Heat Transfer

Degradation of alkanes is a widespread phenomenon in nature, and numerous microorganisms, both prokaryotic and eukaryotic, capable of utilizing these substrates as a carbon and energy source have been isolated and characterized. In this review, we summarize recent advances in the understanding of bacterial metabolism of long-chain n-alkanes. Bacterial strategies for accessing these highly hydrophobic substrates are presented, along with systems for their enzymatic degradation and conversion into products of potential industrial value. We further summarize the current knowledge on the regulation of bacterial long-chain n-alkane metabolism and survey progress in understanding bacterial pathways for utilization of n-alkanes under anaerobic conditions.

Bacterial metabolism of long-chain n-alkanes.

A three-part study encompassing both experiment and analysis has been performed for natural convection in an open-ended vertical channel. One of the principal walls of the channel—the heated wall—was maintained at a uniform temperature, while the other principal wall was unheated. The experiments, which included flow visualization and Nusselt number measurements, were carried out with water in the channel and in the ambient which surrounds the channel. At Rayleigh numbers which exceeded a threshold value, the visualization revealed a pocket of recirculating flow situated adjacent to the unheated wall in the upper part of the channel. The recirculation was fed by fluid drawn into the top of the channel, adjacent to the unheated wall. Average Nusselt numbers for the heated wall were measured over a three orders of magnitude range of a single correlating parameter, which includes the Rayleigh number and the ratio of the channel length to the interwall spacing. The Nusselt numbers were found to be unaffected by the presence of the recirculation zone. Numerical solutions obtained via a parabolic finite difference scheme yielded Nusselt numbers in good agreement with those of experiment. The numerical results covered the Prandtl number range from 0.7 to 10.

Observed Flow Reversals and Measured-Predicted Nusselt Numbers for Natural Convection in a One-Sided Heated Vertical Channel

Deposition of high molecular weight paraffins on the inner wall of subsea production and transportation pipelines continues to be a critical operational problem faced by the petroleum industry. The accumulation of the deposited material on the inner wall of the lines may lead to increased pumping power, decreased flow rate or even to the total blockage of the line, with loss of production and capital investment. The present paper presents a critical review of the research effort devoted to the understanding and modeling of the basic deposition mechanisms that control the wax deposition processes. Molecular diffusion of paraffin has been identified as the dominant deposition mechanism. Most deposition models available in the literature make use of molecular diffusion as the sole mechanism for predicting spatial and temporal distributions of paraffin deposits. However, the study of the literature conducted in the present paper evealed that there is not enough experimental evidence to support this a...

A Critical Review of the Modeling of Wax Deposition Mechanisms

Vertical-channel natural convection spanning between the fully-developed limit and the single-plate boundary-layer limit

Experiences de visualisation de l'ecoulement et du transfert de chaleur dans l'eau pour etudier l'effet de l'inclinaison θ sur la convection naturelle dans un canal a parois paralleles. On fait varier l'ecartement adimensionnel entre les parois (S/H), le mode de chauffage, et la difference de temperature entre la paroi et l'air ambiant (nombre de Rayleigh Ra s ). Obtention d'une correlation entre Nu s , Ra s , S/H et θ

Luis Fernando Alzuguir Azevedo

Papers

Observed Flow Reversals and Measured-Predicted Nusselt Numbers for Natural Convection in a One-Sided Heated Vertical Channel

A Critical Review of the Modeling of Wax Deposition Mechanisms

Vertical-channel natural convection spanning between the fully-developed limit and the single-plate boundary-layer limit

Natural Convection in Open-Ended Inclined Channels

Pulsed air jet impingement heat transfer