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.

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.

A Nonlinear Tension Control Scheme for Web Transport Through Heating Processes

2015 ◽  
Author(s):  
Youwei Lu ◽  
Prabhakar R. Pagilla
Keyword(s):  
Heat Transfer ◽  
Thermal Effects ◽  
Tension Control ◽  
Web Based ◽  
Transfer Processes ◽  
Roll To Roll ◽  
Flexible Material ◽  
Control Scheme ◽  
The Web ◽  
Web Tension

In this paper we develop a model-based nonlinear tension control scheme for transport of flexible materials (webs) through heating processes. Heat transfer processes are widely employed in Roll-to-Roll (R2R) process machines that are used to perform processing operations on a moving web on rollers. Heat transfer processes induce thermal expansion/contraction of the flexible material during transport. Because web strain and elastic modulus are functions of temperature distribution in the web, web tension resulting from elastic strain is affected by heating/cooling of the web. Based on a web tension governing equation that includes both elastic and thermal effects, a nonlinear tension control scheme is developed for control of tension in each tension zone of an R2R system. The control scheme is implemented on an R2R experimental platform containing two heat transfer rollers, one for heating the web and one for subsequently cooling the web prior to winding of the web. Experimental results are presented and discussed.

Heat Transfer Enhancement in Corrugated Pipes

2010 ◽  
Author(s):  
Dennis A. Siginer ◽  
F. Talay Akyildiz
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Heat Transfer Enhancement ◽  
Temperature Fields ◽  
Governing Equations ◽  
Transfer Enhancement ◽  
Exact Analytical Solutions ◽  
Velocity And Temperature Fields ◽  
Steady Laminar

The temperature distribution and heat transfer coefficient are investigated in forced convection with Newtonian fluids in pressure gradient driven hydrodynamically and thermally fully developed steady laminar flow in transversally corrugated pipes. The governing equations are solved by means of the epitrochoid conformal mapping and exact analytical solutions are derived for the velocity and temperature fields without viscous dissipation. The effect of the corrugations and the number of waves on the friction factor, the temperature distribution and the heat transfer enhancement is discussed.

Heat Transfer Analysis of a Finned Solar Air Heater

1988 ◽  
Vol 110 (2) ◽  
pp. 145-155 ◽  
Author(s):  
F. Issacci ◽  
Y. Zvirin ◽  
G. Grossman
Keyword(s):  
Heat Transfer ◽  
Theoretical Method ◽  
Lower Surface ◽  
Temperature Fields ◽  
Heat Transfer Analysis ◽  
Solar Air Heater ◽  
Governing Equations ◽  
Reversed Flow ◽  
Air Heater ◽  
Transfer Processes

A theoretical method is presented for the investigation of a reflective fin solar air heater. The heat transfer processes include radiation in both the solar and IR spectra, mixed convection (forced and natural) in the air and conduction in the fins. The governing equations have been solved numerically to obtain the velocity and temperature fields in the developing and developed flow regions. The efficiency of the finned structure is then calculated, and the results of a parametric study are shown. It has been found that natural convection effects are significant and strong buoyancy leads to separation and reversed flow. The efficiency increases with lower surface emissivity and lower thermal conductivity of the fins.

Analysis of Heat Transfer in Particle Velocity Sensor with Three-Wire Configuration

2020 ◽  
Author(s):  
Zhu Linhui ◽  
Shen Jienan ◽  
Zeng Yibo ◽  
Guo Hang
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Forced Convection ◽  
Analytical Model ◽  
Particle Velocity ◽  
Structure Design ◽  
Distribution Model ◽  
Thermal Perturbation ◽  
Velocity Sensor ◽  
Perturbation Field

Abstract Particle velocity sensor (PVS) plays an important role in determining the type and location of a sound source. In this presentation, analytical model of heat transfer in PVS with a three-wire (SHS) configuration was first presented. By comparing with the thermal diffusion motion, the forced convection exerts a smaller influence on the temperature distribution. Thus, variation in forced convection could induce the formation of a thermal perturbation field. The overall temperature distribution model of a PVS is made up of a steady temperature field and a thermal perturbation field. With the derived model, PVS with SHS configuration has smaller thermal noise and higher signal-to-noise ratio in comparision with a two-wire (SS) configuration under the same conditions. Optimized parameters of structure design and heating power could be obtained via the analysis model. Also, this model gives optimal output performance and frequency-dependent characteristic curve. Numerical results are found to be in good agreement with the analytical solutions and experimental data, which verify the correctness of analytical model and numerical method. The study provides a basis for a theoretical and numerical analysis.

Prediction of Temperature Distribution in a Food Self-Heating System

2010 ◽  
Author(s):  
Son H. Ho ◽  
Muhammad M. Rahman ◽  
Aydin K. Sunol
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Thermal Performance ◽  
Exothermic Reaction ◽  
Heating System ◽  
Food Tray ◽  
Governing Equations ◽  
Heating Unit ◽  
Self Heating ◽  
Heating Profiles

This paper presents a numerical modeling and simulation of heat transfer in a food self-heating unit for group meals. A model of a water-activated heater based on an exothermic reaction was developed. The resulting governing equations of heat conduction and chemical reaction were solved for an analytical approximate solution, to which experimental data found from literature were compared and curve fitted. Then a model of a complete food-heating unit, which includes a stack of four sets of food tray, heating tray, and heater sandwiched between them, as well as the cardboard container, was developed. A system of governing equations for heat transfer in the composite medium for the complete model was solved. Numerical solution of temperature distribution within the food-heating unit is presented. The responses in thermal performance of the heating system to the parameters that influence heating profiles of the heater such as decay constant and heat generation were studied in order to improve the thermal performance of the heating system. The results are useful for designing and optimizing self-heating systems for food served to groups of many people.

Heat Transfer under a Flow of the Highly Viscous Crude Oil in a Buried Oil Pipeline

2021 ◽  
Vol 107 ◽  
pp. 122-128
Author(s):  
Aidar Kadyirov ◽  
Julia Karaeva ◽  
Ekaterina Vachagina
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Temperature Distribution ◽  
Crude Oil ◽  
Air Temperature ◽  
High Viscosity ◽  
Numerical Calculations ◽  
Oil Pipeline ◽  
Transfer Processes ◽  
The Republic

The paper presents a mathematical model and the results of numerical calculations of heat transfer processes during the flow of highly viscous crude oil in an oil pipeline. Comparison with literature data is performed. The samples of oil from the field of the Republic of Tatarstan (Russia) that are characterized by high viscosity were considered as crude oil. The influence of air temperature on the temperature distribution in the soil was investigated. The analysis of the distribution of crude oil temperature along the length of the pipeline was carried out.

scholarly journals Time dependent temperature distribution model in layered human dermal part

2013 ◽  
Vol 8 (2) ◽  
pp. 66-76
Author(s):  
Saraswati Acharya ◽  
DB Gurung ◽  
VP Saxena
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
The Body ◽  
Distribution Model ◽  
Unsteady State ◽  
One Dimensional ◽  
Engineering And Technology ◽  
Governing Differential Equation ◽  
Subcutaneous Tissues ◽  
Sweat Evaporation

The paper developed application of finite element method with linear function in the study of temperature distribution in the layers of dermal part-stratum corneum, stratum germinativum, papillary region, reticular region and subcutaneous tissues as elements. The method is applied to obtain the numerical solution of governing differential equation for one dimensional unsteady state bio-heat transfer using suitable values of parameters that effect the heat transfer in human body. The numerical results obtained are exhibited graphically for various atmospheric temperatures for comparative study of temperature distribution profiles. The loss of heat from the outer surface of the body to the environment is taken due to convection, radiation and sweat evaporation. Kathmandu University Journal of Science, Engineering and Technology Vol. 8, No. II, December, 2012, 66-76 DOI: http://dx.doi.org/10.3126/kuset.v8i2.7327

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 Heat transfer on rotating second grade fluid through an accelerated plate

2017 ◽  
Vol 13 (3) ◽  
Author(s):  
Ahmad Qushairi Mohamad ◽  
Ilyas Khan ◽  
Lim Yeou Jiann ◽  
Sharidan Shafie ◽  
Zaiton Mat Isa ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Linear System ◽  
Physical Problem ◽  
Second Grade ◽  
Governing Equations ◽  
Second Grade Fluid ◽  
Laplace Transform Technique ◽  
Grade Fluid ◽  
Non Linear System

Heat transfer on an unsteady free convection rotating second grade fluid flow, which is flowing through an accelerated plate, is analyzed. The physical problem investigated is described by a coupled, linear system of partial differential equations, with appropriate boundary conditions. Laplace transform technique is applied to determine the analytical solutions of the dimensionless governing equations. The effects of various embedded parameters to the velocity and temperature distribution in the fluid are graphically illustrated and analyzed. The obtained analytical results constitutes a good verification to verify a more advance situation of the physical problem, which is described by a non-linear system and only can be solved by using approximation method. 

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