ISSN:0145-7632    

DOI:10.1080/01457639108939759

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

EDTA is a common additive to reduce the scale formation in industrial boilers. In the present paper, the effect of EDTA concentration on the nucleate boiling heat transfer coefficient of water has been determined with and without CaS04 present as a foulant. The effect of heat flux on the formation of scale deposits is discussed.

ISSN:0145-7632    

DOI:10.1080/01457639108939760

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Experiments have been performed to determine the natural-convection heat transfer characteristics of vertically oriented shrouded heat sinks (finned surfaces) of rectangular profile under uniform heat flux condition applied to the base. The size and configuration of the heat sink, the power dissipated, and the clearance gap between the shroud and the fin tips were varied during the experiments. The heat transfer medium was air. The temperatures were maintained below 150° during the experiments, which is the maximum allowable operation temperature for most silicon-based electronic components. It was found that shrouding, in general, significantly enhances heat transfer from the heat sinks. For a fixed heat flux and heat sink configuration, the maximum temperature on the heat sink dropped as the clearance was increased, attained a minimum, and then started to rise again. The effect of the shroud on 'the maximum temperature and the average Nusselt number is illustrated

ISSN:0145-7632    

DOI:10.1080/01457639108939761

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Steady laminar forced-convection cooling of discrete heated blocks in open and porous matrix channels has been analyzed for different types of coolants, porous material porosities, and mass flow rates. As expected, the low-porosity porous material-filled channel configuration with large Prandtl number fluids flowing at high Reynolds numbers yields the best results in terms of net heat removal. However, the pressure drop for porous material-filled channel flow is measurably higher than that for open-channel flow. As a compromise, using a high porous matrix (say, n = 0.3), the efficiency of the new configuration is 46% higher using water and 58% higher for air when compared with the traditional open-channel cooling system.

ISSN:0145-7632    

DOI:10.1080/01457639108939762

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

At low flow and low pressure conditions, critical heat flux (CHF) data for rod bundle geometry are very limited, and applicable design correlations are almost nonexistent. This paper investigates the applicability of recent CHF correlations developed for uniformly heated vertical annuli (for water mass flux ≤250 kg/m2s, and pressure of 0.118 MPa) to nonuniformly heated rod bundles. Results show that annuli correlations could be used to predict the CHF occurring at the same flow-regime transition in uniformly heated rod bundles. Also, the results demonstrate that the global conditions hypothesis (GCH), in conjunction with the annuli CHF correlations, may be used to predict CHF in nonuniformly heated rod bundles at low flow and low pressure conditions.

ISSN:0145-7632    

DOI:10.1080/01457639108939763

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A rigorous method that takes into consideration stacking pattern is developed and presented for the thermal performance prediction of multistream plate-fin heat exchangers. The method also accounts for transverse conduction of heat through fins. Some published sizing and rating methods dealing with stacking patterns are reviewed. It is shown that rating methods based on a constant surface temperature give optimistic predictions. Transverse heat conduction was found beneficial to the performance of the exchanger. It was found that, in general, patterns that reduced variation of surface temperature through the depth of the stack improved performance. Application of the proposed method is discussed with examples. A procedure for the process design of multistream plate-fin heat exchangers is outlined.

ISSN:0145-7632    

DOI:10.1080/01457639108939764

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor