ISSN:0145-7632    

DOI:10.1080/01457638508939613

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Correlations for heat transfer and pressure drop for in-line and staggered banks of tubes dre suggested. They apply to Re from 1 to 2 × 106and Pr from 0.7 to 104, and a wide range of relative transverse and longitudinal pitches.

ISSN:0145-7632    

DOI:10.1080/01457638508939614

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The pressure drop on the gas-side of an experimental shell-and-tube heat exchanger consisting of a bundle of seven tubes with roughened outer walls inside a smooth hexagonal shell is described. Based on the test results, an analytical method for predicting pressure drop in a heat exchanger with partially smooth and roughened surfaces was developed using the annulus flow model.

ISSN:0145-7632    

DOI:10.1080/01457638508939615

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper presents arguments to prove identical results in determining the most thermohydraulically efficient surface in three comparison studies: the heat flux (at equal pumping powers for the coolant and equal heat transfer surface areas); the pumping power for the coolant (at equal heat fluxes and surface areas); and the heat transfer surface area (at equal heat fluxes and coolant pumping powers). General parameters, St Re/d and ξ(Re3/d3),have been derived. The relationship between these parameters uniquely determines the thermohydraulic efficiency of the convective heat transfer surface. Analysis of equations of the type St Re/d = f( ξ Re3/ d3) helped to identify types of surfaces showing promise for compact viscous-fluid (Re ≤ 2000) heat exchangers. These surfaces are helical ducts, surfaces with short strip fins (StF), wavy fins (WF), and staggered bundles of smooth pipes (St). Heat transfer and friction in laminar flow (Re ≤ 2000) in helical ducts of rectangular cross section with an aspect ratio 0.2 ≤ h/b ≤ 1.2 have been studied in greater detail, and approximating equations have been obtained.

ISSN:0145-7632    

DOI:10.1080/01457638508939616

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper presents the results on the development of methods, algorithms, and computer programs for calculation and optimization parameters of heat exchangers at the design stage. Three classes of mathematical models are considered: one-dimensional models for engineering calculation of real heat exchangers and two- and three-dimensional models, and solutions of conjugated differential equation systems in the approximation of the boundary layer theory. The choice of optimization parameters, control criteria, and restriction functions is discussed in optimization models.

ISSN:0145-7632    

DOI:10.1080/01457638508939617

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A highly effective method for heat transfer enhancement in tube and plate-finned heat exchangers through artificial flow turbulization is proposed. Heat transfer surfaces of different design and their production are developed. A correlation for the increase in heat transfer is found as a function of increasing hydraulic resistance for channels of various cross sections. Results are compared with similar smooth channels with discrete wall flow turbulization. The use of the proposed surfaces allows a 1.5- to 2-fold decrease in the heat exchanger volume, a 3- to 8-fold increase in film boiling heat transfer, a 1.4-fold increase in surface boiling heat transfer, and a 2- to 3.4-fold increase in condensation heat transfer on the outer surfaces of annular grooved tubes as well as a decrease in the salt deposition on the outer and inner surfaces of tubes.

ISSN:0145-7632    

DOI:10.1080/01457638508939618

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Thermohydraulic irregularities may exert considerable effect on thermal performance of high-efficiency heat exchangers. There are two general types of such irregularities: uniform and nonuniform. The present paper presents the results of a study of nonuniform irregularities due to tube diameter and wall thickness deviations, inaccurate bores in tube sheets, initial deflection of bundle tubes, and their deformation accumulating during heat exchanger operation. The total effect on the effectiveness of heat exchanger operation is expressed in a single value referred to as the irregularity parameter ε.

ISSN:0145-7632    

DOI:10.1080/01457638508939619

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor