scholarly journals Numerical Study on Enhanced Heat Transfer by Twisted Tape Inserts inside Tubes

2015 ◽  
Vol 130 ◽  
pp. 256-262 ◽  
Author(s):  
J.D. Zhu ◽  
H. Chen
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Twisted Tape ◽  
Enhanced Heat Transfer

scholarly journals Applications of Compound Nanotechnology and Twisted Inserts for Enhanced Heat Transfer

2020 ◽  
Author(s):  
Hussain H. Al-Kayiem ◽  
Muna S. Kassim ◽  
Saud T. Taher
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Volume Fraction ◽  
Twisted Tape ◽  
Enhanced Heat Transfer ◽  
Maximum Increase ◽  
Industrial Plants ◽  
Nanoparticles Volume Fraction ◽  
Double Pipe

Nanoadditives are a type of heat transfer enhancement techniques adopted in heat exchangers to improve the performance of industrial plants through improvement of the thermal properties of base fluids. Recently, various types of inserts with nanofluids are adopted to enhance the thermal performance of double pipe heat exchangers. In the current article, TiO2/water nanofluid with multiple twisted tape inserts was investigated as a hybrid enhancement technique of heat transfer in straight pipes. The investigations were carried out experimentally and numerically at Reynolds numbers varied from 5000 to 20,000. Using nanofluid with 0.1% TiO2 nanoparticles volume fraction demonstrated enhanced heat transfer with slight increase in pressure drop. Results are showing a maximum increase of 110.8% in Nusselt number in a tube fitted with quintuple twisted tape inserts with 25.2% increase in the pressure drop. However, as the article is representing a part of specified book on heat exchangers, the literature has been extended to provide sufficient background to the reader on the use of nanotech, twisted inserts, and hybrid of compound nanofluids and inserts to enhance heat transfer processes.

A Numerical Study of the Flow and Heat Transfer Characteristics of Outward Convex Corrugated Tubes With Twisted-Tape Insert

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Longbin Yang ◽  
Huaizhi Han ◽  
Yanjun Li ◽  
Xiaoming Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Swirling Flow ◽  
Numerical Study ◽  
Twisted Tape ◽  
Transfer Performance ◽  
Heat Transfer Characteristics ◽  
Corrugated Tube ◽  
Flow And Heat Transfer ◽  
Flow Heat

This work presents a mathematical model for simulating the swirling flow in an outward convex corrugated tube with twisted-tape insert (CT). The synergistic effect on the flow, heat transfer, and friction loss behaviors between the surface-based and fluid-based enhancements is numerically investigated. Renormalized group (RNG) k-ε turbulence model applied in our paper is verified by comparing with experimental results investigated by Manglik and Bergles. Comparisons of the CT and smooth tube with twisted-tape insert (ST) plots are confirmed to investigate the performance differences between them. When comparing the performance of the CT against the ST, the maximum ratio of Nusselt number (Nuc/Nus), ratio of friction factor (f/fs), and overall heat transfer performance (η) values realized in the CT are 1.36, 1.53, and 1.15 times higher, respectively, than the maximum values for those same variables in the ST.

Experimental and Numerical Study on Enhanced Heat Transfer of Solid-Liquid PCM by Ultrasonic Wave

2006 ◽  
Vol 326-328 ◽  
pp. 1145-1148
Author(s):  
Ho Dong Yang ◽  
Yool Kwon Oh
Keyword(s):  
Heat Transfer ◽  
Acoustic Pressure ◽  
Numerical Study ◽  
Acoustic Streaming ◽  
Melting Process ◽  
Oscillating Flow ◽  
Enhancement Ratio ◽  
Ultrasonic Vibrations ◽  
Enhanced Heat Transfer ◽  
Solid Liquid

The present study is investigated the causes of enhanced heat transfer during the melting process of solid-liquid PCM (Phase Change Material) using an ultrasonic vibration. Paraffin (noctadecane) was selected as a PCM and experimental studies were performed as following. Heat transfer coefficient and enhancement ratio of heat transfer was measured, acoustic streaming induced by ultrasonic waves observed using a PIV (Particle Image Velocimetry) and thermally oscillating flow phenomenon observed using an infrared thermal camera during the melting process. For the numerical study, a coupled FE-BEM (Finite Element-Boundary Element Method) was applied to investigate acoustic pressure occurred by acoustic streaming in a medium. And then, the profiles of pressure variation compared with the enhancement ratio of heat transfer. The results of this study revealed that ultrasonic vibrations accompanied the effects like acoustic streaming and thermally oscillating flow. Such effects are a prime mechanism in the overall melting process when ultrasonic vibrations are applied. Also, as the acoustic pressure occurred by acoustic streaming increases, the higher enhancement ratio of heat transfer is obtained.

Sign in / Sign up

Export Citation Format

Share Document