ISSN:0145-7632    

DOI:10.1080/01457639608939869

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Thermal performance improvements through passive and active enhancement methods have been studied intensely for over three decades. Heat exchangers with single-phase lube-side flow are one of the important applications where passive surface-modification methods are popularly employed. Ribs, indentations, spiral flutes, and coil inserts are some common surface modification techniques that are relatively easy to manufacture, are cost effective for many applications, and can be used conveniently for retubing existing heat exchangers. This article describes a comprehensive database that was developed to provide easy access to existing single-phase tube-side heat transfer and pressure drop data for different enhanced tube designs, in a consistent and useful manner. The database contains four files: (1) friction factor data, (2) heat transfer data, (3) tube characteristics, and (4) features of the experiments used by each data source, such as fluid type, boundary conditions, tube material, and tube type. The friction factor database contains nearly 5,000 data points, and the heat transfer database contains more than 4,700 data points. The data encompass more than 360 different tube geometries from over 35 investigations. The information can be used by practicing engineers for validatating and /or developing prediction methods, or to compare or estimate the performance of a specific tube design.

ISSN:0145-7632    

DOI:10.1080/01457639608939870

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This article analyzes heat transfer and friction factor data for single-phase, turbulent flow inside enhanced tubes for different enhanced tube types and from different data sources. Data are given for several enhanced tube types such as extruded tubes (ribs or disruptions with transverse and intermediate helix angles), spirally indented tubes, and tubes with coil inserts. In general, there is good agreement between the heat transfer data for tubes of the same type—manufactured with the same method—from different investigations with essentially the same disruption height, pitch, and helix angle. The variations increase (20–30%) when comparisons are made with similar core geometries but different types such as indented and extruded, or indented and coil inserts. The performance of tubes with coil inserts is very similar to that of tubes with discrete extruded disruptions. There is substantially more deviation of the friction factor data from different sources, even for the same tube type. Also, the analysis shows that more care is required to obtain repeatable and high-quality friction factor data than heat transfer data.

ISSN:0145-7632    

DOI:10.1080/01457639608939871

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0145-7632    

DOI:10.1080/01457639608939872

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Experimental heat transfer data for critical heat flux (CHF) during pool boiling of liquid metals are surveyed. CHF is found to be related to the stability of boiling prior to CHF. A new correlation is given for stable saturated boiling CHF and is shown to give better agreement with data than earlier correlations. This correlation is also applicable to nonmetals. A new correlation is also given for the lower limit of CHF during unstable boiling. Included in the correlation are data on sodium, potassium, cesium, rubidium, and mercury, on plates and cylinders. The limited data available for subcooled CHF are grossly overpredicted by correlations that have been successful for ordinary fluids.

ISSN:0145-7632    

DOI:10.1080/01457639608939873

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The observation by Maday in 1974 that the Schmidt-Duffin solution to the optimal fin profile problem was flawed due to neglect of the slant height factor led to a new solution—actually, a demonstration of the ill-posedness of the question—by Snider. The present article proves mathematically that omission of this factor leads inevitably to underestimation of the heat transfer capability of any fin. Additionally, a perturbation scheme for estimating the correction for this effect is derived for configurations with low generalized Biot numbers, and a revised assessment of the performance of the Schmidt fin is presented.

ISSN:0145-7632    

DOI:10.1080/01457639608939874

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Simple and reliable, these melting-point standards find uses in a variety of temperature-measuring applications throughout industry.

ISSN:0145-7632    

DOI:10.1080/01457639608939875

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor