A Review on the Heat-Transfer Performance and Pressure-Drop Characteristics of Various Enhanced Tubes

Abstract

The enhanced tube is a kind of the passive technique for improving the thermal performance of the heat exchangers with a little increase of the friction penalty. They have stated to use instead of the common smooth tubes for designing of the heat exchangers. The size of these heat exchangers can be reduced considerably by using the enhanced tubes instead of smooth tubes. Normally, they are divided into four groups: the corrugated tube, ribbed tube, grooved tube, and fluted tube. Compared with the common smooth tube, many researchers reported that use of the enhanced tubes dramatically increases the heat-transfer performance, both theoretically and experimentally. Focusing on the advantages of the enhanced tubes, this article summarizes the published studies on the heat-transfer and pressure-drop characteristics of the enhanced tubes, both experimental and quantitative investigations.

Numerical Investigation on Heat and Flow Characteristics of Temperature-Sensitive Ferrofluid in a Square Cavity

“…The ferrofluid generally consisted of magnetite nanosized particle of around 1 to 100 nm and carrier liquid such as water, oils, and hydrocarbons with the aid of surfactants in a continuous carrier phase. It can be controlled by both magnitude and direction of an external magnetic field and temperature [1][2][3][4][5][6][7][8][9][10][11][12]. In addition, because of the nanosized magnetic particles consisting of the ferrofluids and the surfactant attached to magnetic particles, the ferrofluid could be prevented from particles sticking to each other or precipitate with Brownian motion [2].…”

“…In addition, because of the nanosized magnetic particles consisting of the ferrofluids and the surfactant attached to magnetic particles, the ferrofluid could be prevented from particles sticking to each other or precipitate with Brownian motion [2]. Therefore, the ferrofluid could be applied for various industrial fields: enhancement and depression of the heat transfer of the thermal devices, magnetic sealing, damping and bearing of machines, energy conversion system, drug delivery for disease curing, optical devices, micro-/nanofluidic devices, and so forth [3][4][5].…”

Performance of multiple mini-tube heat exchangers as an internal heat exchanger of a vapor-injection cycle heat pump

“…Even though there are various enhanced tubes available [15], plain straight tubes were considered in this study since the tube diameter should be small to construct MMT heat exchangers. The convective heat transfer coefficient of turbulent single-phase flow in a plain tube was estimated using the Gnielinski [16] correlation as follows:…”

The effect of manifold in liquid storage tank applied to solar combisystem

“…In order to increase the total efficiency, a higher circulation rate is essential for the fluid flowing in the collector loop. High fluid velocity on the tank-side of a solar thermal system can enable high heat exchanger performance [13,14] but intense mixing caused by the high velocity does not admit the employment of diffuser and manifold; especially, manifold is not almost used.…”