Modeling of Temperature Distribution in Moving Webs in Roll-to-Roll Manufacturing

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Youwei Lu ◽  
Prabhakar R. Pagilla
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Thermal Strain ◽  
Heat Transfer Model ◽  
Operating Conditions ◽  
Transfer Model ◽  
Roll To Roll ◽  
Flexible Material ◽  
Process Line ◽  
The Web

A heat transfer model that can predict the temperature distribution in moving flexible composite materials (webs) for various heating/cooling conditions is developed in this paper. Heat transfer processes are widely employed in roll-to-roll (R2R) machines that are used to perform processing operations, such as printing, coating, embossing, and lamination, on a moving flexible material. The goal is to efficiently transport the webs over heating/cooling rollers and ovens within such processes. One of the key controlled variables in R2R transport is web tension. When webs are heated or cooled during transport, the temperature distribution in the web causes changes in the mechanical and physical material properties and induces thermal strain. Tension behavior is affected by these changes and thermal strain. To determine thermal strain and material property changes, one requires the distribution of temperature in moving webs. A multilayer heat transfer model for composite webs is developed in this paper. Based on this model, temperature distribution in the moving web is obtained for the web transported on a heat transfer roller and in a web span between two adjacent rollers. Boundary conditions that reflect many types of heating/cooling of webs are considered and discussed. Thermal contact resistance between the moving web and heat transfer roller surfaces is considered in the derivation of the heat transfer model. Model simulations are conducted for a section of a production R2R coating and fusion process line, and temperature data from these simulations are compared with measured data obtained at key locations within the process line. In addition to determining thermal strain in moving webs, the model is valuable in the design of heating/cooling sources required to obtain a certain desired temperature at a specific location within the process line. Further, the model can be used in determining temperature dependent parameters and the selection of operating conditions such as web speed.

scholarly journals A Heat Transfer Model for Graphene Deposition on Ni and Cu Foils in a Roll-to-Roll Plasma Chemical Vapor Deposition System

2021 ◽  
Author(s):  
Majed Alrefae ◽  
Timothy S. Fisher
Keyword(s):  
Heat Transfer ◽  
Chemical Vapor Deposition ◽  
Temperature Distribution ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
Roll To Roll

Abstract High-throughput production is a major bottleneck for integration of graphene-based technologies in existing and future applications. Here, a heat transfer model is developed to optimize large-scale deposition of graphene on Ni and Cu foils in a roll-to-roll plasma chemical vapor deposition (CVD) system. Temperature distributions in Ni and Cu foils during deposition are recorded with in situ temperature measurements using near-IR optical emission spectroscopy. The model indicates that foil movement significantly affects the temperature distribution and cooling rate of the foil. Consequently, graphene growth on Cu is limited to lower web speeds for which the foil temperature is higher and the residence time in the plasma is longer. On the other hand, graphene can be deposited on Ni at relatively higher web speeds due to moderately high diffusion rate of carbon in Ni and increased cooling rates with higher web speed. Critical limitations in the production rates of graphene using roll-to-roll CVD process exist due to significant effects of web speed on the temperature distribution of the substrate. The thermal analysis approach reported here is expected to aid in enhancing the throughput of graphene production in roll-to-roll CVD systems.

scholarly journals Fast three-dimensional heat transfer model for computing internal temperatures in the bearing housing of automotive turbochargers

2018 ◽  
Vol 21 (8) ◽  
pp. 1286-1297 ◽  
Author(s):  
Antonio Gil ◽  
Andrés Omar Tiseira ◽  
Luis Miguel García-Cuevas ◽  
Tatiana Rodríguez Usaquén ◽  
Guillaume Mijotte
Keyword(s):  
Heat Transfer ◽  
Coke Formation ◽  
Three Dimensional ◽  
Heat Transfer Model ◽  
Operating Conditions ◽  
Thermal Design ◽  
Working Fluid ◽  
Transfer Model ◽  
Lumped Model ◽  
Bearing System

Each of the elements that make up the turbocharger has been gradually improved. In order to ensure that the system does not experience any mechanical failures or loss of efficiency, it is important to study which engine-operating conditions could produce the highest failing rate. Common failing conditions in turbochargers are mostly achieved due to oil contamination and high temperatures in the bearing system. Thermal management becomes increasingly important for the required engine performance. Therefore, it has become necessary to have accurate temperature and heat transfer models. Most thermal design and analysis codes need data for validation; often the data available fall outside the range of conditions the engine experiences in reality leading to the need to interpolate and extrapolate disproportionately. This article presents a fast three-dimensional heat transfer model for computing internal temperatures in the central housing for non-water cooled turbochargers and its direct validation with experimental data at different engine-operating conditions of speed and load. The presented model allows a detailed study of the temperature rise of the central housing, lubrication channels, and maximum level of temperature at different points of the bearing system of an automotive turbocharger. It will let to evaluate thermal damage done to the system itself and influences on the working fluid temperatures, which leads to oil coke formation that can affect the performance of the engine. Thermal heat transfer properties obtained from this model can be used to feed and improve a radial lumped model of heat transfer that predicts only local internal temperatures. Model validation is illustrated, and finally, the main results are discussed.

Study on Effective Radial Thermal Conductivity of Gas Flow through a Methanol Reactor

2015 ◽  
Vol 13 (1) ◽  
pp. 103-112 ◽  
Author(s):  
Kun Lei ◽  
Hongfang Ma ◽  
Haitao Zhang ◽  
Weiyong Ying ◽  
Dingye Fang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Reynolds Number ◽  
Temperature Distribution ◽  
Large Scale ◽  
Gas Flow ◽  
Fixed Bed ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Particle Reynolds Number

Abstract The heat conduction performance of the methanol synthesis reactor is significant for the development of large-scale methanol production. The present work has measured the temperature distribution in the fixed bed at air volumetric flow rate 2.4–7 m3 · h−1, inlet air temperature 160–200°C and heating tube temperature 210–270°C. The effective radial thermal conductivity and effective wall heat transfer coefficient were derived based on the steady-state measurements and the two-dimensional heat transfer model. A correlation was proposed based on the experimental data, which related well the Nusselt number and the effective radial thermal conductivity to the particle Reynolds number ranging from 59.2 to 175.8. The heat transfer model combined with the correlation was used to calculate the temperature profiles. A comparison with the predicated temperature and the measurements was illustrated and the results showed that the predication agreed very well with the experimental results. All the absolute values of the relative errors were less than 10%, and the model was verified by experiments. Comparing the correlations of both this work with previously published showed that there are considerable discrepancies among them due to different experimental conditions. The influence of the particle Reynolds number on the temperature distribution inside the bed was also discussed and it was shown that improving particle Reynolds number contributed to enhance heat transfer in the fixed bed.

Modeling the Effects of Heat Transfer Processes on Material Strain and Tension in Roll to Roll Manufacturing

2013 ◽  
Author(s):  
Youwei Lu ◽  
Prabhakar R. Pagilla
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Distribution Model ◽  
Tension Zone ◽  
Governing Equations ◽  
Flexible Materials ◽  
Transfer Processes ◽  
Roll To Roll ◽  
Average Modulus ◽  
The Web

This paper develops governing equations for material strain and tension based on a temperature distribution model when the flexible materials (often called webs) are transported on rollers through heat transfer processes within roll-to-roll (R2R) processing machines. Heat transfer processes are employed widely in R2R systems that contain process operations such as printing, coating, lamination, etc., which require heating/cooling of the moving web material. The heat transfer processes introduce the thermal expansion/contraction of the material and changes in the elastic modulus. Thus, the temperature distribution in the moving material affects the strain distribution in the material. Because of change in strain as well as modulus as a function of temperature, tension in the material resulting from elastic strain is also affected by heating/cooling of the web. To obtain the temperature distribution, two basic heat transfer modes are considered: web wrapped on a heat transfer roller and the web span between two consecutive rollers. The governing equations for strain is then obtained using the law of conservation of mass considering the temperature effects. Subsequently, a governing equation for web tension is obtained by assuming the web is elastic with the modulus varying with temperature; an average modulus is considered for defining the constitutive relation between web strain and tension. Since it is difficult to obtain measurement of tension using load cell rollers within heat transfer processes, a tension observer is designed. To evaluate the developed governing equations, numerical simulations for a single tension zone consisting of a heat transfer roller, a web span, and a driven roller are conducted. Results from these numerical model simulations are presented and discussed.

Specific Absorption Rate and Temperature Increase in Human Eye Subjected to Electromagnetic Fields at 900 MHz

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Teerapot Wessapan ◽  
Phadungsak Rattanadecho
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Electromagnetic Fields ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Specific Absorption ◽  
Eye Model ◽  
Human Eye

Human eye is one of the most sensitive parts of the entire human body when exposed to electromagnetic fields. These electromagnetic fields interact with the human eye and may lead to cause a variety of ocular effects from high intensity radiation. However, the resulting thermo-physiologic response of the human eye to electromagnetic fields is not well understood. In order to gain insight into the phenomena occurring within the human eye with temperature distribution induced by electromagnetic fields, a detailed knowledge of absorbed power distribution as well as temperature distribution is necessary. This study presents a numerical analysis of specific absorption rate (SAR) and heat transfer in the heterogeneous human eye model exposed to electromagnetic fields. In the heterogeneous human eye model, the effect of power density on specific absorption rate and temperature distribution within the human eye is systematically investigated. In particular, the results calculated from a developed heat transfer model, considered natural convection and porous media theory, are compared with the results obtained from a conventional heat transfer model (based on conduction heat transfer). In all cases, the temperatures obtained from the developed heat transfer model have a lower temperature gradient than that of the conventional heat transfer model. The specific absorption rate and the temperature distribution in various parts of the human eye during exposure to electromagnetic fields at 900 MHz, obtained by numerical solution of electromagnetic wave propagation and heat transfer equation, are also presented. The results show that the developed heat transfer model, which is the more accurate way to determine the temperature increase in the human eye due to electromagnetic energy absorption from electromagnetic field exposure.

scholarly journals Verification and Improving the Heat Transfer Model in Radiators in the Wide Change Operating Parameters

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6543
Author(s):  
Mieczysław Dzierzgowski
Keyword(s):  
Heat Transfer ◽  
Mass Flow ◽  
Water Mass ◽  
Heat Transfer Model ◽  
Operating Conditions ◽  
Transfer Model ◽  
Flow Rates ◽  
Wide Range ◽  
Different Types ◽  
Mass Flow Rates

Laboratory measurements and analyses conducted in a wide range of changes of water temperature and mass flow rate for different types of radiators allowed to provides limitations and assessment of the current radiators heat transfer model according to EN 442. The inaccuracy to determinate the radiator heat output according to EN 442, in case of low water mass flow rates may achieve up to 22.3% A revised New Extended Heat Transfer Model in Radiators NEHTMiRmd is general and suitable for different types of radiators both new radiators and radiators existing after a certain period of operation is presented. The NEHTMiRmd with very high accuracy describes the heat transfer processes not only in the nominal conditions—in which the radiators are designed, but what is particularly important also in operating conditions when the radiators water mass flow differ significantly from the nominal value and at the same time the supply temperature changes in the whole range radiators operating during the heating season. In order to prove that the presented new model NEHTMiRmd is general, the article presents numerous calculation examples for various types of radiators currently used. Achieved the high compatibility of the results of the simulation calculations with the measurement results for different types of radiators: iron elements (not ribbed), plate radiators (medium degree ribbed), convectors (high degree ribbed) in a very wide range of changes in the water mass flow rates and the supply temperature indicates that a verified NEHTMiRmd can also be used in designing and simulating calculations of the central heating installations, for the rational conversion of existing installations and district heating systems into low temperature energy efficient systems as well as to directly determine the actual energy efficiency, also to improve the indications of the heat cost allocators. In addition, it may form the basis for the future modification of the European Standards for radiator testing.

Numerical Simulation of Hot Rolled Coil Temperature Field in Hot Coil Box

2011 ◽  
Vol 338 ◽  
pp. 572-575
Author(s):  
Gui Jie Zhang ◽  
Kang Li ◽  
Ying Zi Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Coil Temperature ◽  
Hot Rolled ◽  
Strip Coil ◽  
Good Agreement

The heat transfer model was developed and the heat transfer of the strip coil stay in the hot coil box was analyzed. The temperature distribution of the strip coil was investigated use the model. The measured results are in good agreement with the calculated ones, has a guiding significance to further improve the technology.

Research on heat dissipation design method for motor controller radiator

2019 ◽  
Vol 234 (8) ◽  
pp. 1673-1685
Author(s):  
Huanlong Liu ◽  
Chixin Xie ◽  
Guanpeng Chen ◽  
Zeping Cao
Keyword(s):  
Heat Transfer ◽  
Electric Vehicles ◽  
Heat Dissipation ◽  
Design Method ◽  
Heat Transfer Model ◽  
Operating Conditions ◽  
Transfer Model ◽  
Insulated Gate Bipolar Transistor ◽  
Motor Controller ◽  
Key Factor

With the complication of electric vehicles operating conditions, the damage caused by the overheating of insulated gate bipolar transistor and freewheeling diode that are the core components of the motor controller has become a key factor restricting the development of electric vehicles. The motor controller is primarily cooled by a radiator, and the heat exchange of the radiator includes heat transfer between the heat sources of the motor controller and the radiator walls and heat convection between the cooling medium and the radiator walls. A fluid–solid coupling heat transfer model for analyzing the motor controller was established. The flow field performances and main influencing factors were analyzed, and the correctness of the method was verified by experiments. To improve the design efficiency of the motor controller radiator, a design method based on target temperature, installation position of the liquid cooling radiator, fluid parameters, and heating power was proposed. This method can quickly calculate and evaluate the heat dissipation capability of the radiator. The fluid–solid coupling heat transfer model using this design method is established in computational fluid dynamics software, and the results show that the relative error between the simulation results and the design method results is within 20%.

Numerical investigation of turbocharger turbine temperature field based on conjugate heat transfer

2021 ◽  
pp. 095440892110399
Author(s):  
Liang Peng ◽  
Zhenlei Chen ◽  
Yi Hu
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Model ◽  
Operating Conditions ◽  
Transfer Model ◽  
Traditional Model ◽  
Test Results ◽  
Hypothetical Data ◽  
Volume Method

Aiming at the issues of low accuracy and poor feasibility of the analytical results of the turbocharger turbine temperature field under operating conditions, a full-domain conjugate heat transfer numerical model was established by the conjugate heat transfer and finite volume method. The temperature field characteristics of each component of the turbocharger turbine were analyzed. The numerical and experimental test results were compared and analyzed. The global conjugate heat transfer model avoids the input of a large number of hypothetical data on the interface between fluid and solid in the traditional model, and makes the calculation process closer to the actual situation. Through the comparison with the experimental results, the accuracy of the turbine temperature field obtained by the global conjugate heat transfer model is more reasonable and more accurate than that of the traditional model, which verifies the reliability and accuracy of the global conjugate heat transfer model.

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