ISSN:0145-7632    

DOI:10.1080/01457638608939648

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The phase plane essentially is a plot of heat conduction versus temperature. Given the phase plane of a particular class of extended surfaces, the engineer can quickly execute numerous tactics of design analysis or synthesis, because the plot displays heat dissipation, temperature distribution, and reduced length all on one diagram. A special set of coordinates is proposed, and their universality to all extended surfaces is explored. Working diagrams are presented for straight rectangular and triangular fins. Some numerical examples show how to use the diagrams.

ISSN:0145-7632    

DOI:10.1080/01457638608939649

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A closed analytical expression for calculating the TEMA H-shell F factor ( mean temperature difference correction factor) is derived. The F factor, computed for various values of the number of transfer units ( NTU) and the heat capacity rate ratio ( R) are found to be almost identical to values of the TEMA G-shell F factor over most of the parameter ranges. The difference becomes significant only when NTU is greater than 20 and R is greater than 4. Therefore, this work confirms that, for all practical purposes, the G shell F factor can be substituted for the H-shell F factor. This derivation completes the set of analytical expressions for F factors of all the TEMA shell types

ISSN:0145-7632    

DOI:10.1080/01457638608939650

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The adverse impact of carbon dioxide and air on the thermal performance of condensers used in multistage flash ( MSF) distillation plants is addressed. For normal operating conditions, the inlet gas flow rates are not sufficient to affect the thermal performance significantly. The heat duty for a typical condenser design is then determined for a broad range of entering noncondensable gas flow rates and vent flow rates. When the inlet steam/C02mass ratio falls below about 250, the thermal performance is strongly affected by the noncondensable gases. When the vent flow rate approaches the minimum vapor/gas ratio based on the coolant temperature, a sharp drop in thermal performance also occurs. However, the thermal performance is not sensitive to the vent flow rate when it is about twice this minimum value.

ISSN:0145-7632    

DOI:10.1080/01457638608939651

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A dynamic one-dimensional model of a simple rectangular natural circulation loop with tube bundles in the two vertical legs has been simulated. A supporting experimental study using water at atmospheric pressure as the working fluid has been conducted to obtain data to verify the model. Good agreement was obtained between the predicted and measured mixed-mean fluid temperatures and surface temperatures of the tube bundle as well as the loop piping and insulation temperatures at several locations around the system. A number of different simulations and tests have been performed and are discussed. In general, at steady state there was less than 7% deviation between the model predictions and the test data, which indicates that the one-dimensional model is capable of predicting the transient temperature response of the loop structural components and of the circulating fluid.

ISSN:0145-7632    

DOI:10.1080/01457638608939652

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

An assessment of several promising techniques that use surface tension forces to enhance film condensation heat transfer on horizontal tubes is made. Recent progress on integral-fin tubes is stressed, including experimental findings on fin spacing, geometry, and material and the latest theoretical developments for predicting performance. Condensation heat transfer enhancement on wire-wrapped tubes is also examined, as well as the use of nonwetting strips and porous drainage devices. The effect of condensate inundation on plain and enhanced tubes is reviewed briefly, and future research directions are discussed.

ISSN:0145-7632    

DOI:10.1080/01457638608939653

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

One of the techniques used by designers of shell-and-tube heat exchangers when they encounter a potential flow-induced vibration problem is to shift from a tube bundle with segmental baffles to one with double-segmental baffles. This results in a split of the flow into either half of the shell with lower velocities and makes it possible to reduce the unsupported tube span length while keeping below a given allowable pressure drop. Tests were performed as a part of a systematic study of water flow-induced vibration in industrial-size heat exchangers. Results for nine different double-segmental baffled bundle configurations are presented. Comparison of the results with those for similar segmental baffled bundles shows that higher flows can be tolerated without developing damaging flow-induced vibration.

ISSN:0145-7632    

DOI:10.1080/01457638608939654

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0145-7632    

DOI:10.1080/01457638608939655

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Heat transfer research at the government laboratory is driven by mission needs and fueled by a rapidly growing ability to measure and compute very complex problems. Solutions to such problems require a well-organized team approach, and government laboratories are in a key position to organize effective government-industry-university research teams.

ISSN:0145-7632    

DOI:10.1080/01457638608939656

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The competition-induced transformation of the industrial environment, currently under way, is placing new demands on the engineering profession. The consequent opportunities and challenges facing the thermal community in the United States during the next decade are explored. It is suggested that the thermal community can take the lead in reversing the growing alienation of academic research from industrial needs by redefining its research agenda, by altering the format of technical meetings, by broadening and deepening training in heat transfer, and by supporting the establishment of ‘product family’ institutes at leading U.S. universities

ISSN:0145-7632    

DOI:10.1080/01457638608939657

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor