Heat transfer, efficiency and turn-down ratio of a dynamic radiative heat exchanger

Author(s):  
Rydge B. Mulford ◽  
Matthew R. Jones ◽  
Brian D. Iverson
Author(s):  
Yao Li ◽  
Haiqing Si ◽  
Jingxuan Qiu ◽  
Yingying Shen ◽  
Peihong Zhang ◽  
...  

Abstract The plate-fin heat exchanger has been widely applied in the field of air separation and aerospace due to its high specific surface area of heat transfer. However, the low heat transfer efficiency of its plate bundles has also attracted more attention. It is of great significance to optimize the structure of plate-fin heat exchanger to improve its heat transfer efficiency. The plate bundle was studied by combining numerical simulation with experiment. Firstly, according to the heat and mass transfer theory, the plate bundle calculation model of plate-fin heat exchanger was established, and the accuracy of the UDF (User-Defined Functions) for describing the mass and heat transfer was verified. Then, the influences of fin structure parameters on the heat and mass transfer characteristics of channel were discussed, including the height, spacing, thickness and length of fins. Finally the influence of various factors on the flow field performance under different flow states was integrated to complete the optimal design of the plate bundle.


Author(s):  
H. Zabiri ◽  
V. R. Radhakrishnan ◽  
M. Ramasamy ◽  
N. M. Ramli ◽  
V. Do Thanh ◽  
...  

The Crude Preheat Train (CPT) is a set of large heat exchangers which recover the waste heat from product streams back to preheat the crude oil. The overall heat transfer coefficient in these heat exchangers may be significantly reduced due to fouling. One of the major impacts of fouling in CPT operation is the reduced heat transfer efficiency. The objective of this paper is to develop a predictive model using statistical methods which can a priori predict the rate of the fouling and the decrease in heat transfer efficiency in a heat exchanger in a crude preheat train. This predictive model will then be integrated into a preventive maintenance diagnostic tool to plan the cleaning of the heat exchanger to remove the fouling and bring back the heat exchanger efficiency to their peak values. The fouling model was developed using historical plant operating data and is based on Neural Network. Results show that the predictive model is able to predict the shell and tube outlet temperatures with excellent accuracy, where the Root Mean Square Error (RMSE) obtained is less than 1%, correlation coefficient R2 of approximately 0.98 and Correct Directional Change (CDC) values of more than 90%. A preliminary case study shows promising indication that the predictive model may be integrated into a preventive maintenance scheduling for the heat exchanger cleaning.


2014 ◽  
Vol 1008-1009 ◽  
pp. 927-933
Author(s):  
Hai Jiang Yang ◽  
Ming Li ◽  
Xiao Ye Xue ◽  
Yan Liu ◽  
Kui Huang

In this paper, the heat transfer rate of parallel flow heat exchanger was obtained in the condition of non-uniform flow distribution by 3D numerical simulation. The maximum theoretical heat transfer rate of parallel flow heat exchanger was obtained through 1D calculation. Ultimately, the correlation of the influence of non-uniform flow distribution on heat transfer efficiency was obtained by the comparative analysis of non-uniform flow distribution and heat transfer efficiency and regression calculation. It was found that the forecasted heat transfer efficiency error of correlation was within 2%.


2015 ◽  
Vol 19 (4) ◽  
pp. 1397-1402 ◽  
Author(s):  
Zhao-Chun Wu ◽  
Xiang-Ping Zhu

A comparison of heat transfer efficiency between the heat pipe and tube bundles heat exchanger is made based on heat transfer principle and the analysis of thermal characteristics. This paper argues that although heat pipe has the feature of high axial thermal conductivity, to those cases where this special function of heat transfer is unnecessary, heat pipe exchanger is not a high efficient heat exchanger when it is just used as a conventional heat exchanger in the industrial fields. In turn, there are some deficiencies for heat pipe exchanger, such as complicated manufacturing process, critical requirements for manufacturing materials, etc. which leads to a higher cost in comparison to a tubular heat exchanger. Nonetheless, due to its diverse structural features and extraordinary properties, heat pipe exchanger still has wide applications on special occasions.


2021 ◽  
Vol 7 (1) ◽  
pp. 262-269
Author(s):  
J. Li ◽  
J. Shan ◽  
Z. Guo ◽  
A. Levtsev

In recent years, the enhancement of heat transfer by pulsating flow has become a research hotspot. A great deal of work has been done in the past, with remarkable results, to achieve better heat transfer rates. How to improve the efficiency of heat exchanger is always a research topic. In this paper, pulsating air flow is formed by standard ventilation grille and electric actuator, and the pulsating air flow is guided through two-stage heat exchanger to study the influence of pulsating air flow on heat transfer efficiency. The experimental results show that the heat transfer efficiency can be improved by pulsating flow and the heat recovery efficiency can be reduced by increasing the flow rate of the heating medium.


2022 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Zhiwei Wu ◽  
Caifu Qian

Baffles with holes in different diameters (or HDD baffles) and conically-corrugated tubes are respectively longitudinal flow baffle and high-efficiency heat exchange tubes proposed by the author. In this paper, vibrations of tube bundles with HDD baffles and fluid flow as well as heat transfer inside conically-corrugated tubes were numerically simulated, and the heat exchanger with conically-corrugated tubes and HDD baffles was tested for the heat transfer efficiency. It is found that compared with the traditional segmental baffles, tube bundle vibrations in heat exchangers, if using the HDD baffles, can be significantly reduced. Regarding heat transfer efficiency, conically-corrugated tubes are much better than smooth tubes and even better than other high-efficiency heat transfer tubes. Compared with the traditional heat exchangers, heat exchangers constructed with conically-corrugated tubes and the HDD baffles can provide better heat transfer efficiency and less tube bundle vibration.


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