• Journal of Mechanical Science and Technology
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• v.15 no.11
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• pp.1555-1562
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• 2001

In a conventional shell-and-tube heat exchanger, fluid contacts with tubes flowing up and down in a shell, therefore there is a defect in the heat transfer with tubes due to the stagnation portions . Fins are attached to the tubes in order to increase heat transfer efficiency, but there exists a limit. Therefore, it is necessary to improve heat exchanger performance by changing the fluid flow in the shell. In this study, a highly efficient shell-and-tube heat exchanger with spiral baffle plates is simulated three-dimensionally using a commercial thermal-fluid analysis code, CFX4.2. In this type of heat exchanger, fluid contacts with tubes flowing rotationally in the shell. It could improve heat exchanger performance considerably because stagnation portions in the shell could be removed. It is proved that the shell-and-tube heat exchanger with spiral baffle plates is superior to the conventional heat exchanger in terms of heat transfer.

• Journal of Power System Engineering
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• v.16 no.4
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• pp.24-29
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• 2012

The numerical analysis by using CFX 11.0 commercial code was done for prediction of fluid flow and thermal field in the vertical heat exchanger. The present experimental studies were also conducted to investigate the effects of circulating solid particles on the fluid flow and temperatures in the fluidized bed vertical shell and tube type heat exchanger with counterflow, at which the solid particles of glasses (3 $mm{\Phi}$) were used in the fluidized bed with a smooth tube. The effect of circulation on the distance(L) of tube inlet and baffle plate was also examined. The present experimental and numerical results showed that the particles in the distance (Ds) of 15 mm showed a more efficient circulation without stacked the space and the LMTD(Log Mean Temperature Difference) in the fluidized bed type was much lower than that in the typical type shell and tube heat exchanger.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1149-1155
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• 2004

An experimental study was performed to investigate the characteristics of heat transfer in a vertical type fluidized bed shell-and-tube type heat exchanger with corrugated tube. Seven different solid particles having the same volume were circulated in the heat of exchanger. The effects of various parameters such as water flow rates, particle geometries, materials, and corrugated tube geometries were investigated. The present work showed that the higher thermal capacities of materials and the geometries closer to the spherical one have higher heat transfer performances. In addition, heat transfer coefficients in the corrugated tubes were a little higher than those in the smooth tubes.

• Journal of agriculture & life science
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• v.44 no.4
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• pp.29-43
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• 2010

The numerical analysis by using CFX 11.0 commercial code was done for proper design of the heat exchanger. The present experimental studies were also conducted to investigate the effects of circulating solid particles on the characteristics of fluid flow, heat transfer and cleaning effect in the fluidized bed vertical shell and tube type heat exchanger with counterflow, at which a variety of solid particles such as glass ($3mm{\Phi}$), aluminum ($2{\sim}3mm{\Phi}$), steel ($2{\sim}2.5mm{\Phi}$), copper ($2.5mm{\Phi}$) and sand ($2{\sim}4mm{\Phi}$) were used in the fluidized bed with a smooth tube. Seven different solid particles have the same volume, and the effects of various parameters such as water flow rates, particle diameter, materials and geometry were investigated. The present experimental and numerical results showed that the flow velocity range for collision of particles to the tube wall was higher with heavier density solid particles, and the increase in heat transfer was in the order of sand, copper, steel, aluminum, and glass. This behavior might be attributed to the parameters such as surface roughness or particle heat capacity.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.367-375
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• 2014

In numbers of kinds of heat exchanger, the shell-tube heat exchanger is the most commonly used type of heat exchanger in the industry field. In order to improve the thermal performance of the heat exchanger, this study was analyzed heat transfer characteristics according to arrangement of baffle and direction of baffle and bump phase of baffle about shell-tube heat exchanger using appropriate SST (Shear Stress Transport) turbulence model for flow separation and boundary layer analysis. As the boundary condition for CFD (Computational Fluid Dynamics) analysis, the inlet temperature of shell side was constantly 344 K and the variation of the water flow rate was 6, 12, 18 and 24 l/min. As the result of analysis, zigzag baffle arrangement enhances heat transfer rate and pressure drop. Furthermore, in the direction of the baffle, heat transfer rate is more improved with vertical type and angle $45^{\circ}$ type than existing type, and pressure drop was little difference. Also, the bump shape of baffle surface contributes to heat transfer rate and pressure drop improvement due to the increased heat transfer area. Through analysis results, we knew that the increase of the heat transfer was influenced by flow separation, fluid residual time, contact area with the tube, flow rate, swirl and so on.