Ultrasonic Welding of Soft Polymer and Metal: A Preliminary Study

2019 ◽  
Author(s):  
Yuquan Meng ◽  
Dingyu Peng ◽  
Qasim Nazir ◽  
Gowtham Kuntumalla ◽  
Manjunath C. Rajagopal ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
Waste Heat ◽  
Ultrasonic Welding ◽  
Operating Conditions ◽  
Innovative Products ◽  
Soft Polymer ◽  
Heat Exchanges ◽  
Future Work ◽  
Welding Processes ◽  
Soft Polymers

Abstract Joining soft polymers and metals is receiving increasing attention in both industry and academia to enable the manufacturing of innovative products. One motivation arises from the production of next-generation heat exchanges, the structure of which is primarily composed of polymers and metals. Waste heat coming from low temperature exhaust gas stream is significant in industries in the U.S. However, traditional heat exchangers that are available to recover heat in the presence of small temperature difference are large and costly, restricting the wide application of such heat exchangers. To address this challenge, a hybrid materials design is proposed to achieve a balance between thermal conductivity and mechanical strength. High quality requirement induced by the changing operating conditions necessitates a strong bonding between polymers and copper. In this research, the possibility of using ultrasonic welding, which is conventionally employed to join dissimilar or similar metal layers, is explored. Preliminary results from welding experiments and tensile shear tests reveal that two bonding modes exist in the welding of PET and copper. Furthermore, analysis of power signals collected during welding shows that one can potentially monitor and optimize welding processes using monitoring signals. It is concluded from this study that ultrasonic welding has excellent potential in joining soft polymers and metals. Future work is also discussed on the process improvement and mechanism investigation.

scholarly journals Component-Oriented Modeling of a Micro-Scale Organic Rankine Cycle System for Waste Heat Recovery Applications

2021 ◽  
Vol 11 (5) ◽  
pp. 1984
Author(s):  
Ramin Moradi ◽  
Emanuele Habib ◽  
Enrico Bocci ◽  
Luca Cioccolanti
Keyword(s):  
Electric Power ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Pump Efficiency ◽  
Micro Scale

Organic Rankine cycle (ORC) systems are some of the most suitable technologies to produce electricity from low-temperature waste heat. In this study, a non-regenerative, micro-scale ORC system was tested in off-design conditions using R134a as the working fluid. The experimental data were then used to tune the semi-empirical models of the main components of the system. Eventually, the models were used in a component-oriented system solver to map the system electric performance at varying operating conditions. The analysis highlighted the non-negligible impact of the plunger pump on the system performance Indeed, the experimental results showed that the low pump efficiency in the investigated operating range can lead to negative net electric power in some working conditions. For most data points, the expander and the pump isentropic efficiencies are found in the approximate ranges of 35% to 55% and 17% to 34%, respectively. Furthermore, the maximum net electric power was about 200 W with a net electric efficiency of about 1.2%, thus also stressing the importance of a proper selection of the pump for waste heat recovery applications.

Application of Equipartition of Entransy Loss Principle in Heat Exchangers

2012 ◽  
Vol 629 ◽  
pp. 699-703
Author(s):  
Chun Sheng Guo ◽  
Wen Jing Du ◽  
Lin Cheng
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Optimization Design ◽  
Loss Rate ◽  
Plate Heat Exchanger ◽  
Loss Minimization ◽  
Plate Heat ◽  
Entransy Loss ◽  
Heat Exchanges ◽  
Minimization Approach

The entransy loss minimization approach for the heat exchanger optimization design was established by Guo Z Y; the study based Guo Z Y’s works, found relationship between the entransy loss uniformity and the heat exchanger performance and the expression of the local entransy loss rate for heat convection was derived, numerical results of the heat transfer in a chevron plate heat exchanger and helix baffle heat exchanger show that the larger entransy loss uniformity factor appear in about Re=2000 and the entransy loss uniformity factor of chevron plate heat exchanges higher than helix baffle one.

Optimization of a Sintering Waste Heat Power Unit

2014 ◽  
Vol 1008-1009 ◽  
pp. 897-900
Author(s):  
Xue Min Gong ◽  
Jiu Lin Yang ◽  
Chen Wang
Keyword(s):  
Power Generation ◽  
Power Unit ◽  
Waste Heat ◽  
Steam Pressure ◽  
Operating Conditions ◽  
Parameters Optimization ◽  
Heat Power ◽  
Optimal Value ◽  
Generation Capacity ◽  
Main Steam

An optimization was performed for a sintering waste heat power unit with all data obtained in the site and under the unit normal operating conditions. The physical and mathematical model for the process of cooling and generation is established, which makes the net power generation as an objective function of the cooling machine imported ventilation, the thickness of sinter and the main steam pressure. Optimizing for single parameter, we found that each parameter had an optimal value for the system. In order to further optimize the system's operating parameters, genetic algorithm was used to make the combinatorial optimization of the three parameters. Optimization results show that power generation capacity per ton is increased by13.10%, and net power generation is increased by 16.17%. The optimization is instructive to the operation of sintering waste heat power unit.

scholarly journals Efficient storage and recovery of waste heat by phase change material embedded within additively manufactured grid heat exchangers

2021 ◽  
Vol 181 ◽  
pp. 121846
Author(s):  
Maryam Roza Yazdani ◽  
Alpo Laitinen ◽  
Valtteri Helaakoski ◽  
Lorant Katona Farnas ◽  
Kirsi Kukko ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Heat Exchangers ◽  
Waste Heat ◽  
Efficient Storage ◽  
Change Material

Analysis of circumferentially welded thin-walled cylinders to study the effects of tack weld orientations and joint root opening on residual stress fields

2009 ◽  
Vol 223 (5) ◽  
pp. 1037-1049 ◽  
Author(s):  
N U Dar ◽  
E M Qureshi ◽  
A M Malik ◽  
M M I Hammouda ◽  
R A Azeem
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Arc Welding ◽  
Operating Conditions ◽  
Stress Fields ◽  
Welded Structures ◽  
Prime Concern ◽  
Thin Walled ◽  
Tack Weld ◽  
Welding Processes

In recent years, the demand for resilient welded structures with excellent in-service load-bearing capacity has been growing rapidly. The operating conditions (thermal and/or structural loads) are becoming more stringent, putting immense pressure on welding engineers to secure excellent quality welded structures. The local, non-uniform heating and subsequent cooling during the welding processes cause complex thermal stress—strain fields to develop, which finally leads to residual stresses, distortions, and their adverse consequences. Residual stresses are of prime concern to industries producing weld-integrated structures around the globe because of their obvious potential to cause dimensional instability in welded structures, and contribute to premature fracture/failure along with significant reduction in fatigue strength and in-service performance of welded structures. Arc welding with single or multiple weld runs is an appropriate and cost-effective joining method to produce high-strength structures in these industries. Multi-field interaction in arc welding makes it a complex manufacturing process. A number of geometric and process parameters contribute significant stress levels in arc-welded structures. In the present analysis, parametric studies have been conducted for the effects of a critical geometric parameter (i.e. tack weld) on the corresponding residual stress fields in circumferentially welded thin-walled cylinders. Tack weld offers considerable resistance to the shrinkage, and the orientation and size of tacks can altogether alter stress patterns within the weldments. Hence, a critical analysis for the effects of tack weld orientation is desirable.

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 Air-Side Thermal-Hydraulic Performance of Flat-Tube Heat Exchangers With Louvered, Wavy, and Plain Fins Under Dry and Wet Conditions

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Young-Gil Park ◽  
Anthony M. Jacobi
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Hydraulic Performance ◽  
Operating Conditions ◽  
Geometrical Parameters ◽  
Flat Tube ◽  
Parametric Effects ◽  
Dry And Wet Conditions ◽  
Wet Surface ◽  
Friction Performance

The air-side thermal-hydraulic performance of flat-tube aluminum heat exchangers is studied experimentally for conditions typical to air-conditioning applications, for heat exchangers constructed with serpentine louvered, wavy, and plain fins. Using a closed-loop calorimetric wind tunnel, heat transfer and pressure drop are measured at air face velocities from 0.5 m/s to 2.8 m/s for dry- and wet-surface conditions. Parametric effects related to geometry and operating conditions on heat transfer and friction performance of the heat exchangers are explored. Significant differences in the effect of geometrical parameters are found for dry and wet conditions. For the louver-fin geometry, using a combined database from the present and the previous studies, empirical curve-fits for the Colburn j- and f-factors are developed in terms of a wet-surface multiplier. The wet-surface multiplier correlations fit the present database with rms relative residuals of 21.1% and 24.4% for j and f multipliers, respectively. Alternatively, stand-alone Colburn j and f correlations give rms relative residuals of 22.7% and 29.1%, respectively.

Sign in / Sign up

Export Citation Format

Share Document