Intensification of heat transfer in a liquid film evaporator

2014 ◽  
Vol 68 (12) ◽  
Author(s):  
Pavol Timár ◽  
Lenka Nemsilová ◽  
Pavel Timár ◽  
Ján Stopka ◽  
Ladislav Štibrányi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchangers ◽  
Transformer Oil ◽  
Transfer Efficiency ◽  
Outlet Temperature ◽  
Falling Film ◽  
Heat Transfer Efficiency ◽  
Mass Flows ◽  
Pipe Heat

AbstractInfluence of the heat exchanger shape on the heat transfer efficiency investigated. Heat transfer efficiency of two vertical pipe-in-pipe heat exchangers, one with a straight wall and the other with a twisted wall were compared. Both heat exchangers worked on the principle of liquid falling film. Electric transformer oil was used as the heated liquid and water vapor at atmospheric pressure was used as the heating agent. Oil was just heated, not evaporated during the experiments. Oil inlet and outlet temperature were measured at six different oil mass flows. Heat flux and heat flux density in the straight- and twisted-wall heat exchangers were compared. Mathematical model was built to verify the possibility of the oil outlet temperature prediction.

Development of Heat Exchanger Fouling Model and Preventive Maintenance Diagnostic Tool

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
H. Zabiri ◽  
V. R. Radhakrishnan ◽  
M. Ramasamy ◽  
N. M. Ramli ◽  
V. Do Thanh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Predictive Model ◽  
Diagnostic Tool ◽  
Preventive Maintenance ◽  
Heat Exchangers ◽  
Waste Heat ◽  
A Priori ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency

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.

scholarly journals HEAT TRANSFER EFFICIENCY OF KLEEMENKO CYCLE HEAT EXCHANGERS

2008 ◽  
Author(s):  
W. A. Little ◽  
J. G. Weisend ◽  
John Barclay ◽  
Susan Breon ◽  
Jonathan Demko ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency

scholarly journals A CFD investigation and heat transfer augmentation of double pipe heat exchanger by employing helical baffles on shell and tube side

2021 ◽  
pp. 300-300
Author(s):  
Sobhanadri Anantha ◽  
Senthilkumar Gnanamani ◽  
Vivekanandan Mahendran ◽  
Venkatesh Rathinavelu ◽  
Ramkumar Rajagopal ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
The Other ◽  
Outlet Temperature ◽  
Shell Side ◽  
Shell And Tube ◽  
Double Pipe ◽  
Pipe Heat

The inclusion of baffles in a double pipe heat exchanger is becoming increasingly important as it improves the heat exchanger's performance. CFD analysis is used in this paper to investigate the performance of double pipe heat exchangers with and without helical baffles on both shell tube sides. The 3D Computation Fluid Dynamics (CFD) model was created in Solid Works, and the FloEFD software was used to analyze the conjugate Heat Transfer between the heat exchanger's tube and shell sides. Heat transfer characteristic like Outlet temperature of shell and tube are investigated along with pressure drop on shell and tube side. Based on CFD results of Double Pipe Heat exchanger with helical baffle on both shell side and tube side (Type 4) gives the better results than the other type of heat exchangers with an increased pressure drop than the others, results reveals that type 4 outlet temperature of shell side is 8% higher and on tube side it is 5.5% higher, also pressure drop on shell side is 12% higher and on tube side it is 42% higher than the other types.

scholarly journals Numerical Study on Heat Transfer Efficiency of Regenerative Thermal Oxidizers with Three Canisters

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1621
Author(s):  
Guangyi Pu ◽  
Xiaoyin Li ◽  
Fangyang Yuan
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Numerical Study ◽  
Operation Time ◽  
Transfer Efficiency ◽  
Physical Parameters ◽  
Outlet Temperature ◽  
Heat Transfer Efficiency ◽  
Switch Time ◽  
Volatile Organic

The heat transfer efficiency of a regenerative thermal oxidizer with three canisters used for volatile organic compounds treatment was studied using numerical simulation methods. A one-dimensional model that took into account the variation of physical parameters with temperature was built. The results show that the preheating temperature and outlet temperature tend to be stable as the operation time is increased. The heat transfer efficiency of equipment was mainly evaluated by heat recovery efficiency and energy recovery ratio under steady state conditions, which was affected by the inlet gas flow and temperature, valve switch time, combustion temperature, materials and porosity of the regenerative medium, and packing height. With the increase in packing cross-sectional area and packing height, the increase in heat transfer efficiency leads to an increase in equipment cost. Simultaneously, the shorter the valve switch time and the higher the density of the regenerative medium battery also help to improve the heat transfer efficiency without blocking equipment. Unless the removal efficiency of volatile organic compound treatment is reduced, it is recommended to reduce the inlet and combustion temperatures.

scholarly journals Study on Behavior of the Heat Exchanger with Conically-Corrugated Tubes and HDD Baffles

2022 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Zhiwei Wu ◽  
Caifu Qian
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Tube Bundle ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency ◽  
Tube Bundles ◽  
Different Diameters ◽  
Better Than

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.

scholarly journals Diamond-Shaped Extended Fins for Heat Transfer Enhancement in a Double-Pipe Heat Exchanger: An Innovative Design

2021 ◽  
Vol 11 (13) ◽  
pp. 5954
Author(s):  
Muhammad Ishaq ◽  
Amjad Ali ◽  
Muhammad Amjad ◽  
Khalid Saifullah Syed ◽  
Zafar Iqbal
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Adaptive Finite Element Method ◽  
Transfer Enhancement ◽  
Enhanced Heat Transfer ◽  
Frictional Loss ◽  
Special Cases ◽  
Double Pipe ◽  
Pipe Heat

Heat transfer enhancement in heat exchangers results in thermal efficiency and energy saving. In double-pipe heat exchangers (DPHEs), extended or augmented fins in the annulus of the two concentric pipes, i.e., at the outer surface of the inner pipe, are used to extend the surface of contact for enhancing heat transfer. In this article, an innovative diamond-shaped design of extended fins is proposed for DPHEs. This type of fin is considered for the first time in the design of DPHEs. The triangular-shaped and rectangular-shaped fin designs of DPHE, available in the literature, can be recovered as special cases of the proposed design. An h-adaptive finite element method is employed for the solution of the governing equations. The results are computed for various performance measures against the emerging parameters. The results dictate that the optimal configurations of the diamond-shaped fins in the DPHE for an enhanced heat transfer are recommended as follows: If around 4–6, 8–12, or 16–32 fins are to be placed in the DPHE, then the height of the fins should be 20%, 80%, or 100%, respectively, of the annulus width. If frictional loss of heat is also to be considered, then for fin-heights of 20–80% and 100% of the annulus width, the placement of 4 and 8 diamond-shaped fins, respectively, is recommended for an enhanced heat transfer. These recommendations are for the radii ratio (i.e., the ratio of the inner pipe radius to that of the outer pipe) of 0.25. The recommendations are be modified if the radii ratio is altered.

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