Bubble columns are gas- liquid contactors that are widely used in chemical and bio- chemical industries. High mixing that result in high heat and mass transfer rates are amongst their advantages. Heat transfer in a bubble column having a bundle of heaters investigated and the variation of heat transfer coefficient with variation in heaters pitch to diameter ratios in a bundle of heaters reporte...

Basic understanding of the process of coolant heat transfer inside an engine is an indispensable prerequisite to devise an infallible cooling strategy. Coolant flow and its heat transfer affect the cooling efficiency, thermal load of heated components, and thermal efficiency of a diesel engine. An efficient approach to studying cooling system for diesel engine is a 3D computational fluid dynami...

The effect of surface roughness on nucleate boiling heat transfer is not clearly understood. This study is devised to conduct detailed heat transfer and bubble measurements during boiling on a heater surface with controlled roughness. This second of two companion papers presents an analysis of heat transfer and bubble ebullition in nucleate boiling with new measures of surface roughness: area r...

sustainable development would be a key solution for climate change and renewable energy plays an important role in this policy. recently, according to increase of co2 emission and other relevant impacts, solar energy has been gaining more attentions from policy makers. thus, compound parabolic concentrators collectors are considered as one of the promising applications from solar thermal advant...

Heat transfer coefficient in nucleate pool boiling near critical heat flux at least one orderhigher than the convectional heat transfer modes. In this paper, an experimental setup isdesigned and fabricated to investigate the mechanism of heat transfer from boiling surface tobulk liquid near critical heat flux. The images of pool boiling near the high heat flux regionreveals that the individual ...

Improving heat transfer and performance in a radial, finned, shell and tube heat exchanger is studied in this study. According to the second law of thermodynamics, the most irreversibilities of convective heat transfer processes are due to fluid friction and heat transfer via finite temperature difference. Entransy dissipations are due to the irreversibilities of convective heat transfer. There...

External heat transfer predictions are performed for two-dimensional turbine blade cascades. The Reynolds averaged Navier-Stokes equations with algebraic (Baldwin-Lomax) and two-equation (low-Re k ?) turbulence closures are solved with an explicit Runge-Kutta time-marching nite volume method. Comparisons with measurement for subsonic and transonic cascades show good agreement in some cases, but...