scholarly journals Design and Development of Innovative Steam Injection for High-Temperature Short-Time Liquid Foods

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 161
Author(s):  
Wilasinee Sangsom ◽  
Chouw Inprasit
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Steam Injection ◽  
Transfer Efficiency ◽  
Optimal Conditions ◽  
Steam Temperature ◽  
Pineapple Juice ◽  
Heat Transfer Efficiency ◽  
High Temperature Short Time ◽  
Circular Holes

Jet impingement has been effective in reducing the process time and improvement of product quality in various industrial applications, such as textile and paper drying, electronic cooling, glass quenching and food processing. The current work applied innovative steam injection to liquid food continuous sterilization. The multiple impingement jets of steam and product came together in the impingement tank. The effects were investigated on the Reynolds number, steam temperature and jet-to-target spacing (H/d), sterilization temperature and heat transfer efficiency in water and pineapple juice tests. The Reynolds number was based on the nozzle configuration and liquid flow rate. The study investigated product injection plates formed using two, three or four circular holes (diameter 2 mm), steam injection plates with six, nine or twenty circular holes (diameter 1 mm), steam temperatures of 120, 125 or 130 °C and H/d values of 1, 3, 5 or 7. The different options were tested with water to determine the optimal conditions, and then tested with pineapple juice. The results showed that the optimal conditions from water testing that provided the highest heat transfer efficiency occurred with two jet nozzles, six steam injection plates, a steam temperature of 120 °C and an H/d value of 1.

Study on Flow Structure Behind Multiple Circular Cylinders in a Tandem Arrangement Under the Effect of Magnetic Field

CFD Letters ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 126-136
Author(s):  
Nur Marissa Kamarul Baharin ◽  
Mohd Azan Mohammed Sapardi ◽  
Ahmad Hussein Abdul Hamid ◽  
Syed Noh Syed Abu Bakar
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Flow Structure ◽  
Critical Reynolds Number ◽  
Nuclear Fusion ◽  
Fusion Reaction ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency

The fast-moving technologies and the increasing rate of growth population indicates that the demand for energy will continue to be spiking and prominent in the discussion of the upcoming future. Therefore, to cater to the need for sustainable and clean energy, the idea of nuclear fusion is proposed and studied. Because the nuclear fusion reaction happens at a high temperature, the concept of magnetic field is adapted to the nuclear or plasma fusion reaction. The energy will be harnessed inside a blanket module of the fusion reaction plant. However, the presence of the magnetic field affects the fluid flow inside the blanket module where it reduces the heat transfer efficiency in the channel. This research examines the flow structure behind multiple bluff bodies arranged in tandem in a channel under the influence of a magnetic field with the aim to increase the heat transfer efficiency inside the channel. The effect of gap ratio, G/h = [1-2.4] and Hartmann friction parameter, H = [0-800], were analysed to determine the critical Reynolds number and Nusselt number. It was found that the presence of the downstream cylinder with gap ratios, G/h = 1.2, 1.4 and 1.6, causes the flow to be unsteady at a lower Reynolds number compared to those of a single cylinder. The multiple cylinders proved to increase the Nusselt number. Increasing the Hartmann friction parameter increases the critical Reynolds number and decreases the Nusselt number.

CFD-based structure optimization of plate bundle in plate-fin heat exchanger considering flow and heat transfer performance

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yao Li ◽  
Haiqing Si ◽  
Jingxuan Qiu ◽  
Yingying Shen ◽  
Peihong Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Field Performance ◽  
High Specific Surface Area ◽  
Calculation Model ◽  
Air Separation ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency

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.

scholarly journals Thermo-Hydraulic Performance of U-Tube Borehole Heat Exchanger with Different Cross-Sections

2021 ◽  
Vol 13 (6) ◽  
pp. 3255
Author(s):  
Aizhao Zhou ◽  
Xianwen Huang ◽  
Wei Wang ◽  
Pengming Jiang ◽  
Xinwei Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Heat Resistance ◽  
Cross Sections ◽  
Three Dimensional ◽  
Thermal Response ◽  
Transfer Efficiency ◽  
Cross Sectional ◽  
Heat Transfer Efficiency ◽  
Oval Tube

For reducing the initial GSHP investment, the heat transfer efficiency of the borehole heat exchange (BHE) system can be enhanced to reduce the number or depth of drilling. This paper proposes a novel and simple BHE design by changing the cross-sectional shape of the U-tube to increase the heat transfer efficiency of BHEs. Specifically, in this study, we (1) verified the reliability of the three-dimensional numerical model based on the thermal response test (TRT) and (2) compared the inlet and outlet temperatures of the different U-tubes at 48 h under the premise of constant leg distance and fluid area. Referent to the circular tube, the increases in the heat exchange efficiencies of the curved oval tube, flat oval tube, semicircle tube, and sector tube were 13.0%, 19.1%, 9.4%, and 14.8%, respectively. (3) The heat flux heterogeneity of the tubes on the inlet and outlet sides of the BHE, in decreasing order, is flat oval, semicircle, curved oval, sector, and circle shapes. (4) The temperature heterogeneity of the borehole wall in the BHE in decreasing order is circle, sector, curved oval, flat oval, and semicircle shapes. (5) Under the premise of maximum leg distance, referent to the heat resistance of the tube with a circle shape at 48 h, the heat exchange efficiency of the curved oval, flat oval, semicircle, and sector tubes increased 12.6%, 17.7%, 10.3%, and 7.8%, respectively. (6) We found that the adjustments of the leg distance and the tube shape affect the heat resistance by about 25% and 12%, respectively. (7) The flat-oval-shaped tube at the maximum leg distance was found to be the best tube design for BHEs.

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.

The Influence of Welding Parameters on Heat Transfer Efficiency of Hybrid Pulsed Nd: YAG/GTAW Welding

2015 ◽  
Vol 1088 ◽  
pp. 807-813
Author(s):  
Miao Xia Xie ◽  
Lin Jie Zhang
Keyword(s):  
Heat Transfer ◽  
Nd:Yag Laser ◽  
Welding Process ◽  
Transfer Efficiency ◽  
304 Stainless Steel ◽  
Welding Parameters ◽  
Hybrid Welding ◽  
Pulsed Nd:Yag Laser ◽  
Heat Transfer Efficiency ◽  
Cross Section Area

In this work, effects of major welding parameters, such as laser power, defocus distance of laser beam, inter-heat sources distance and welding speed, on weld geometry were investigated for pulsed Nd:YAG laser/GTAW hybrid welding of 304 stainless steel. Heat transfer efficiency of pulsed Nd:YAG laser/GTAW hybrid welding process was quantitativly analyzed based on rosenthal equation. Furthermore, melting efficiency was determined from the measured welding seams cross section area.

Boundary Slope Control in Topology Optimization for Additive Manufacturing: For Self-Support and Surface Roughness

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Cunfu Wang ◽  
Xiaoping Qian ◽  
William D. Gerstler ◽  
Jeff Shubrooks
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Density Gradient ◽  
Transfer Efficiency ◽  
Global Constraints ◽  
Optimization Approach ◽  
Heat Transfer Efficiency ◽  
Boundary Slope

This paper studies how to control boundary slope of optimized parts in density-based topology optimization for additive manufacturing (AM). Boundary slope of a part affects the amount of support structure required during its fabrication by additive processes. Boundary slope also has a direct relation with the resulting surface roughness from the AM processes, which in turn affects the heat transfer efficiency. By constraining the minimal boundary slope, support structures can be eliminated or reduced for AM, and thus, material and postprocessing costs are reduced; by constraining the maximal boundary slope, high-surface roughness can be attained, and thus, the heat transfer efficiency is increased. In this paper, the boundary slope is controlled through a constraint between the density gradient and the given build direction. This allows us to explicitly control the boundary slope through density gradient in the density-based topology optimization approach. We control the boundary slope through two single global constraints. An adaptive scheme is also proposed to select the thresholds of these two boundary slope constraints. Numerical examples of linear elastic problem, heat conduction problem, and thermoelastic problems demonstrate the effectiveness and efficiency of the proposed formulation in controlling boundary slopes for additive manufacturing. Experimental results from metal 3D printed parts confirm that our boundary slope-based formulation is effective for controlling part self-support during printing and for affecting surface roughness of the printed parts.

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