ISSN:0145-7632    

DOI:10.1080/01457639308939796

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

To provide information on application and operational problems of heat exchangers in New Zealand, a comprehensive questionnaire was sent to 3500 potential users of heat transfer equipment. In this report, the method of investigation is described and heat exchanger data are presented. These data are then discussed with respect to their occurrence for various heat exchanger applications, industries, and heat exchanger types.

ISSN:0145-7632    

DOI:10.1080/01457639308939797

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In the present study, attention is paid to some indispensable principles for making a useful adjustment of seal clearances in a rotary regenerator, illustrated by means of examples. First, the effect of leakages and their distribution within such a heat exchanger on the efficiency of a steam power plant is presented. In this way it is shown that not only total leakage but also the distribution of the leakages within the rotary regenerator have an important influence on the efficiency. An interesting conclusion appears here—reduction in total leakage may even bring about a drop in power plant efficiency if distribution of leakages changes unfavorably. Second, in order to show in which rotor state seal clearances should be adjusted, appropriate examples of experimental results concerning radial seal clearances in the hot and cold rotor state are compared. Next, on the basis of a leakage network and some experimental data before and after reduction in radial seal clearances, the effect of reduction in seal clearances on the total leakage and its distribution within a rotary regenerator is shown. Thus the value of such a reduction for the efficiency of a steam power plant is evaluated.

ISSN:0145-7632    

DOI:10.1080/01457639308939798

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In some countries (e.g., South Africa), important market areas for air-source heat pumps are situated high above sea level, and it is therefore necessary to know what the influence of height is on the performance of heat pumps for water healing. Therefore, a study was conducted that predicts the influence of height on the coefficient of performance (COP) of air-source heat pumps. An expression was derived that gives the heat transfer to the evaporator of a heat pump as a junction of air density and enthalpy as well as the outside heat transfer coefficient. This expression was used to predict the influence of height above sea level on COP. The results were verified by means of a simulation study. It was concluded that height has little influence on COP if the evaporator of the heat pump is wet on the air side. A more significant weakening in the performance occurs, however, when the air side of the evaporator is dry.

ISSN:0145-7632    

DOI:10.1080/01457639308939799

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In order to design an efficient heat exchanger accurately, a better understanding is needed regarding the foulants that are deposited on the heat transfer surfaces of heat exchangers to recover energy from hot flue gases in industrial furnaces. This article briefly describes the design and fabrication of a gas-side fouling measuring device, and its testing in an industrial environment. It describes probe fabrication, instrumentation used for recording the data, field test location, tests performed, and data analysis. The conclusions of the tests performed are summarized. Although fouling deposits on the probe were minimal, the tests proved that the probe is capable of measuring fouling in a harsh industrial environment.

ISSN:0145-7632    

DOI:10.1080/01457639308939800

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A finite-element approach is used to study the two-dimensional performance of a straight fin of rectangular profile operating in a convecting environment. The analysis includes the effects of internal heat generation, anisotropy of fin material, base temperature elevation (depression), and unequal heat transfer coefficients for tip and main convection surfaces. Numerical results are presented showing the impact of these effects on the heat removal capability of the fin. The graphical information provided is believed to be useful for predicting the performance of a two-dimensional rectangular fin under more general and realistic conditions.

ISSN:0145-7632    

DOI:10.1080/01457639308939801

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor