A consideration of thermal burns caused by a mat with hot-water circulation. Analysis of heat transfer in a body contacting a mat with hot-water circulation.

Abstract-The present work investigates the enhancement of heat transfer by using different number of circular fins (8, 10, 12, 16, and 20) in double tube counter flow heat exchanger experimentally. The fins are made of copper with dimensions 66 mm OD, 22 mm ID and 1 mm thickness. Each fin has three of 14 mm diameter perforations located at 120o from each to another. The fins are fixed on a straight smooth copper tube of 1 m length, 19.9 mm ID and 22.2 mm OD. The tube is inserted inside the insulated PVC tube of 100 mm ID. The cold water is pumped around the finned copper tube, inside the PVC, at mass flow rates range (0.01019 - 0.0219) kg/s. The Reynold's number of hot water ranges (640 - 1921). The experiment results are obtained using six double tube heat exchanger (1 smooth tube and the other 5 are finned one). The results, illustrated that the heat transfer coefficient proportionally with the number of fin. The results also showed that the enhancement ratio of heat transfer for finned tube is higher than for smooth tube with (9.2, 10.2, 11.1, 12.1 13.1) times for number of fins (8, 10, 12, 16 and 20) respectively.

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Tube Banks Heat Transfer Enhancement Using Conical Fins

ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting: Volume 1, Symposia – Parts A, B, and C ◽

10.1115/fedsm-icnmm2010-31236 ◽

2010 ◽

Author(s):

Ignacio Carvajal-Mariscal ◽

Florencio Sanchez-Silva ◽

Georgiy Polupan

Keyword(s):

Heat Transfer ◽

Heat Exchange ◽

Pressure Drop ◽

Finned Tube ◽

Hot Water ◽

Experimental Results ◽

Tube Bank ◽

Finned Tubes ◽

Tube Banks ◽

Annular Fins

In this work the heat transfer and pressure drop experimental results obtained in a two step finned tube bank with conical fins are presented. The tube bank had an equilateral triangle array composed of nine finned tubes with conical fins inclined 45 degrees in respect with the tube axis. The heat exchange external area of a single tube is approximately 0.07 m2. All necessary thermal parameters, inlet/outlet temperatures, mass flows, for the heat balance in the tube bank were determined for different air velocities, Re = 3400–18400, and one constant thermal charge provided by a hot water flow with a temperature of 80 °C. As a result, the correlations for the heat transfer and pressure drop calculation were obtained. The experimental results were compared against the analytical results for a tube bank with annular fins with the same heat exchange area. It was found that the proposed tube bank using finned tubes with conical fins shows an increment of heat transfer up to 58%.

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Thermal Characteristics Analysis on Multi- Heat Pipe Induced Heat Exchanger

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.b1034.1292s219 ◽

2019 ◽

Vol 9 (2S2) ◽

pp. 143-147 ◽

Cited By ~ 1

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Pipe ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Cold Water ◽

Hot Water ◽

Working Fluid ◽

Physical Parameters

In this investigation of multi heat pipe induced in heat exchanger shows the developments in heat transfer is to improve the efficiency of heat exchangers. Water is used as a heat transfer fluid and acetone is used as a working fluid. Rotameter is set to measure the flow rate of cold water and hot water. To maintain the parameter as experimental setup. Then set the mass flow rate of hot water as 40 LPH, 60LPH, 80 LPH, 100LPH, 120 LPH and mass flow rate of cold water as 20 LPH, 30 LPH, 40 LPH, 50 LPH, and 60 LPH. Then 40 C, 45 ºC, 50 ºC, 55 C, 60 ºC are the temperatures of hot water at inlet are maintained. To find some various physical parameters of Qc , hc , Re ,, Pr , Rth. The maximum effectiveness of the investigation obtained from condition of Thi 60 C, Tci 32 C and 100 LPH mhi, 60 LPH mci the maximum effectiveness attained as 57.25. Then the mhi as 100 LPH, mci as 60 LPH and Thi at 40 C as 37.6%. It shows the effectiveness get increased about 34.3 to the maximum conditions.

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Study on Sewage Sludge Drying System With Built-in Solar Drying Bed

E3S Web of Conferences ◽

10.1051/e3sconf/202123701041 ◽

2021 ◽

Vol 237 ◽

pp. 01041

Author(s):

Zhipan Gu ◽

Jichun Yang ◽

Jing Liu ◽

Leren Tao ◽

Ye Zhang ◽

...

Keyword(s):

Heat Transfer ◽

Sewage Sludge ◽

Radiation Heat Transfer ◽

Middle Layer ◽

Bottom Layer ◽

Mass Transfer Process ◽

Hot Water ◽

Solar Drying ◽

Hot Air ◽

Air Supply

In this paper, the renewable energy solar energy is used as the heat source. The combination of solar drying bed and traditional hot air drying can effectively reduce energy consumption and operation cost. The drying chamber is divided into three layers. The top air supply outlet supplies hot air, the middle layer places wet sludge, and the bottom layer uses hot water coil to dry the sludge. The whole drying process is a heat and mass transfer process with convective heat transfer and radiation heat transfer. After analysis and comparison with traditional energy drying, it is found that drying 97.5kg of sewage sludge will save 79% energy, save 12.84 kg of standard coal, reduce 32 kg of carbon dioxide and 1.284 kg of sulphur dioxide.

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Performance Analysis and Design Optimization of Shell and Tube Heat Exchangers

10.21203/rs.3.rs-407371/v1 ◽

2021 ◽

Author(s):

praveen math

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Exchangers ◽

Pressure Loss ◽

Fluid Flows ◽

Hot Water ◽

Flow Conditions ◽

Shell Side ◽

Shell And Tube ◽

Side Flow

Abstract Shell and Tube heat exchangers are having special importance in boilers, oil coolers, condensers, pre-heaters. They are also widely used in process applications as well as the refrigeration and air conditioning industry. The robustness and medium weighted shape of Shell and Tube heat exchangers make them well suited for high pressure operations. The aim of this study is to experiment, validate and to provide design suggestion to optimize the shell and tube heat exchanger (STHE). The heat exchanger is made of acrylic material with 2 baffles and 7 tubes made of stainless steel. Hot fluid flows inside the tube and cold fluid flows over the tube in the shell. 4 K-type thermocouples were used to read the hot and cold fluids inlet and outlet temperatures. Experiments were carried out for various combinations of hot and cold water flow rates with different hot water inlet temperatures. The flow conditions are limited to the lab size model of the experimental setup. A commercial CFD code was used to study the thermal and hydraulic flow field inside the shell and tubes. CFD methodology is developed to appropriately represent the flow physics and the procedure is validated with the experimental results. Turbulent flow in tube side is observed for all flow conditions, while the shell side has laminar flow except for extreme hot water temperatures. Hence transition k-kl-omega model was used to predict the flow better for transition cases. Realizable k- epsilon model with non-equilibrium wall function was used for turbulent cases. Temperature and velocity profiles are examined in detail and observed that the flow remains almost uniform to the tubes thus limiting heat transfer. Approximately 2/3 rd of the shell side flow does not surround the tubes due to biased flow contributing to reduced overall heat transfer and increased pressure loss. On the basis of these findings an attempt has been made to enhance the heat transfer by inducing turbulence in the shel l side flow. The two baffles were rotated in opposite direction to each other to achieve more circulation in the shell side flow and provide more contact with tube surface. Various positions of the baffles were simulated and studied using CFD analysis and th e results are summarized with respect to heat transfer and pressure loss.

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Thermal Analysis of the Effects of Multifaceted Conditions on Performance of Shell-and-Tube Heat Exchanger

European Journal of Engineering Research and Science ◽

10.24018/ejers.2021.6.1.2325 ◽

2021 ◽

Vol 6 (1) ◽

pp. 69-75

Author(s):

Taiwo O. Oni ◽

Ayotunde A. Ojo ◽

Daniel C. Uguru-Okorie ◽

David O. Akindele

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Parallel Flow ◽

Hot Water ◽

Inlet Temperature ◽

Fiber Glass ◽

Counter Flow ◽

Tube Heat Exchanger ◽

Shell And Tube ◽

Flow Configurations

A shell-and-tube heat exchanger which was subjected to different flow configurations, viz. counter flow, and parallel flow, was investigated. Each of the flow configurations was operated under two different conditions of the shell, that is, an uninsulated shell and a shell insulated with fiber glass. The hot water inlet temperature of the tube was reduced gradually from 60 oC to 40 oC, and performance evaluation of the heat exchanger was carried out. It was found that for the uninsulated shell, the heat transfer effectiveness for hot water inlet temperature of 60, 55, 50, 45, and 40 oC are 0.243, 0.244, 0.240, 0.240, and 0.247, respectively, for the parallel flow arrangement. For the counter flow arrangement, the heat transfer effectiveness for the uninsulated shell are 2.40, 2.74, 5.00, 4.17, and 2.70%, respectively, higher than those for the parallel flow. The heat exchanger’s heat transfer effectiveness with fiber-glass-insulated shell for the parallel flow condition with tube hot water inlet temperatures of 60, 55, 50, 45, and 40 oC are 0.223, 0.226, 0.220, 0.225, and 0.227, respectively, whereas the counter flow condition has its heat transfer effectiveness increased by 1.28, 1.47, 1.82, 1.11, and 1.18%, respectively, over those of the parallel flow.

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