scholarly journals 3D Numerical Modeling of Laser Assisted Tape Winding Process of Composite Pressure Vessels and Pipes—Effect of Winding Angle, Mandrel Curvature and Tape Width

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2449 ◽  
Author(s):  
Amin Zaami ◽  
Ismet Baran ◽  
Ton C. Bor ◽  
Remko Akkerman
Keyword(s):  
Temperature Distribution ◽  
Bonding Temperature ◽  
Considerable Effect ◽  
Pressure Vessels ◽  
Process Temperature ◽  
Thermoplastic Composites ◽  
Transfer Model ◽  
3D Numerical Modeling ◽  
Helical Winding ◽  
Winding Angle

Advanced thermoplastic composites manufacturing using laser assisted tape placement or winding (LATP/LATW) is a challenging task as monitoring and predicting nip point (bonding) temperature are difficult especially on curved surfaces. A comprehensive numerical analysis of the heat flux and temperature distribution near the nip point is carried out in this paper for helical winding of fiber reinforced thermoplastic tapes on a cylindrically shaped mandrel. An optical ray-tracing technique is coupled with a numerical heat transfer model in the process simulation tool. The developed optical-thermal model predictions were compared with experimental data available in literature to validate its effectiveness. The influences of winding/placement angle, mandrel curvature and tape width on the incident angles, the laser absorbed intensity, and the process temperature distribution are studied extensively using the validated model. Winding/placement angle has a considerable effect on the temperature distribution. Increase in winding angle results in a higher temperature for tape due to more reflections coming from the substrate. On the other hand, substrate temperature decreases as the winding angle increases due to a decrease in the laser incident angles based on the local surface curvature. An increase in mandrel curvature results in higher nip point temperatures for substrate and lower one for tape. Different mandrel sizes for 90 ° placement path do not have a strong effect on the substrate process temperature as for other winding angles because of less curvature change of the corresponding irradiated area. Tape width causes local temperature variations at the edges of the tape/substrate. In order to obtain the desired process temeprature during LATW or LATP processes, the laser intensity distribution on the tape and substrate surfaces should be regulated.

scholarly journals An analytical method to estimate temperature distribution of typical radiant floor cooling systems with internal heat radiation

2021 ◽  
pp. 014459872199800
Author(s):  
Xiaolong Wang ◽  
Wenke Zhang ◽  
Qingqing Li ◽  
Zhenqiang Wei ◽  
Wenjun Lei ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Internal Heat ◽  
Single Layer ◽  
Heat Radiation ◽  
Transfer Model ◽  
Cooling Systems ◽  
Average Temperature ◽  
Floor Surface ◽  
Floor Structure

Radiant floor cooling systems are increasingly used in practice. The temperature distribution on the floor surface and inside the floor structure, especially the minimum and average temperature of floor surface, determines the thermal performance of radiant floor systems. A good temperature distribution of the floor structure is very important to prevent occupant discomfort and avoid possible condensation in summer cooling. In this study, based on the heat transfer model of the single-layer homogeneous floor structure when there is no internal heat radiation in the room, this paper proposes a heat transfer model of single-layer floor radiant cooling systems when the room has internal heat radiation. Using separation variable methods, an analytical solution was developed to estimate temperature distribution of typical radiant floor cooling systems with internal heat radiation, which can be used to calculate the minimum temperature and the average temperature of typical composite floor structure. The analytical solution was validated by experiments. The values of the measured experiments are in a good agreement with the calculations. The absolute error between the calculated and the measured floor surface temperatures was within 0.45°C. The maximum relative error was within 2.31%. Prove that this model can be accepted. The proposed method can be utilized to calculate the cooling capacity of a typical multi-layer composite floor and will be developed in the future study for design of a typical radiant floor cooling system.

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 and Numerical Simulation of Laminated Thermoplastic Composites Manufactured by Laser-Assisted Automatic Tape Placement

2020 ◽  
Vol 35 (5) ◽  
pp. 471-480
Author(s):  
G. Ausias ◽  
G. Dolo ◽  
D. Cartié ◽  
F. Challois ◽  
P. Joyot ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Numerical Model ◽  
Pressure Field ◽  
Processing Parameters ◽  
Thermoplastic Composites ◽  
Final Thickness ◽  
Intimate Contact ◽  
Polymer Flow ◽  
Compaction Force ◽  
Heat Transfer Simulation

Abstract A comprehensive numerical model is developed for the simulation of the laser-assisted automated tape placement process of carbon fiber/thermoplastic composites. After being heated with a laser, the thermoplastic is welded with the help of a consolidation roller onto a substrate made up of layers of tapes bonded onto one another. Under the pressure applied by the roller, the thermoplastic flows and the tape reaches its final thickness. The numerical model is developed in three sequential steps that can be used to identify the required pressure and temperature distribution to achieve a good bond. Firstly, a heat transfer simulation is performed to determine the temperature distribution into the incoming tape under the consolidation roller. Secondly, a rheological model is developed to examine the polymer flow under the roller and to obtain the pressure field. Finally, the consolidation level between the substrate and the tape is investigated through the degree of intimate contact, which is related to the processing parameters such as the roller velocity, the laser power density and the compaction force.

Maximum Condensable Pressure in a Sealed Container With Arbitrary Temperature Distribution

2020 ◽  
Author(s):  
J. I. Watjen ◽  
M. T. Schifano ◽  
M. N. Sexton
Keyword(s):  
Temperature Distribution ◽  
Internal Pressure ◽  
Strong Relationship ◽  
Pressure Vessels ◽  
Large Temperature ◽  
Internal Temperature ◽  
Seal Integrity ◽  
Arbitrary Temperature ◽  
Vapor Mixtures ◽  
Saturated Boiling

Abstract Pressure vessels and sealed canisters are designed to maintain seal integrity under a maximum internal pressure. When the temperature inside the canister rises, the internal pressure rises accordingly. The presence of condensable liquid-vapor mixtures can create a strong relationship between the pressure and temperature. An isothermal container admits a straightforward thermodynamic pressure calculation; however, large temperature gradients inside the container require complex multiphase conjugate heat transfer calculations to predict accurate pressures. A simplified prediction using the peak internal temperature to find the saturated pressure of the condensable fluid may introduce unrealistic pressures when significant fluid mass exists in a cooler location of the container. This work presents methodology to calculate the pressure of a condensable fluid in a sealed container with large internal temperature differences using a two-temperature approach to predict saturated boiling and superheating of the vapor phase. An arbitrary temperature distribution allows for pressure calculations by considering the expected location of the liquid mass and the peak internal temperature. An enthalpy balance provides the effects of the temperature distribution and the peak pressure condition is easily predicted using the proposed method. This work provides a means to calculate the maximum internal pressure of a sealed container with a condensable fluid without the need for complex multiphase computer modeling.

scholarly journals An Analytical Approach to Wet Cooling Towers Based on Functional Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Guo Qianjian ◽  
Xiaoni Qi ◽  
Zheng Wei ◽  
Peng Sun
Keyword(s):  
Functional Analysis ◽  
Temperature Distribution ◽  
Analytical Solution ◽  
Cooling Tower ◽  
Transfer Model ◽  
Cooling Towers ◽  
Contraction Mapping Theorem ◽  
Uniqueness Of The Solution ◽  
Linear Differential ◽  
Analytical Expressions

An analytical solution for computing the temperature distribution of air and water over the height through the cooling tower is so complex that finding the exact solution takes too much time. The purpose of this paper is to present efficient and accurate analytical expressions for the heat and mass transfer model in cooling towers. Based on the method of functional analysis, we derived an analytical solution for temperature distribution of water and air by using the method of solving linear differential equations. The error estimation, the existence, and uniqueness of the solution are given by using Banach contraction mapping theorem. The basic equation of the model on the basis of the additional assumptions on the cooling tower is solved, and the outlet parameters are also obtained.

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 Numerical Simulation and Experimental Study on Temperature Distribution of Self-Lubricating Packing Rings in Reciprocating Compressors

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Jia Xiaohan ◽  
Zhang Qingqing ◽  
Feng Jianmei ◽  
Peng Xueyuan
Keyword(s):  
Temperature Distribution ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Maximum Temperature ◽  
Transfer Model ◽  
Radial Temperature ◽  
Operational Conditions ◽  
External Cooling ◽  
Packing Rings ◽  
Compressor Reliability

The nonuniform abrasion failure and high-temperature thermal failure of packing rings have a significant influence on compressor reliability, particularly that of oil-free compressors. In this study, a test rig was constructed to measure the dynamic temperature of packing rings under different operational conditions in an oil-free reciprocating compressor. The dynamic axial and radial temperature distributions of the packing rings were obtained using an innovative internal temperature testing device that kept the thermocouples and packing box relatively static during compressor operation. A three-dimensional heat transfer model was also developed to analyze the temperature distribution of the packing boxes, piston rod, and cylinder during such operation. Good agreement was observed between the simulation results and experimental data, which showed an average relative error of less than 2.35%. The results indicate that the pressure ratio exerts a significant effect on the axial temperature distribution and determines which packing ring reaches the maximum temperature. They also show the average temperature to rise with an increase in the rotational speed and to fall with an improvement in the external cooling conditions. Finally, the material of the packing rings was found to affect the temperature gradient from their inner to outer surface.

Thermal Aspects in Resistance Welding of Thermoplastic Composites

2003 ◽  
Author(s):  
Darko Stavrov ◽  
Harald E. N. Bersee
Keyword(s):  
Temperature Distribution ◽  
Power Level ◽  
Resistance Welding ◽  
Thermoplastic Composites ◽  
Transient Temperature ◽  
Temperature Profiles ◽  
Stainless Steel Mesh ◽  
Type K ◽  
Glass Fiber Reinforced ◽  
Set Up

This paper presents a comprehensive experimental study on the thermal aspects in resistance welding of thermoplastic composites. A special test set-up was developed to perform the experiments. Glass fiber reinforced polyetherimide was the material used for manufacturing the welding specimens. Stainless steel mesh was used for production of heating elements. The temperature distribution was monitored using type-K thermocouples connected to a data acquisition system. The main objective of the study was investigating a possible solution for the edge effect. Temperature profiles over the weld length and over the weld width were monitored. The focus was on the transient temperature profiles at the edges of the weld. The temperature distribution through the weld thickness was also monitored. The influence of factors like insulation and power level was investigated. Finally, conclusions are drawn and options for improving the temperature distribution and modification of the models are being discussed.

A more accurate method for predicting the stresses in a flat steel ribbon wound pressure vessel

1999 ◽  
Vol 213 (8) ◽  
pp. 787-793 ◽  
Author(s):  
J Y Zheng ◽  
P Xu ◽  
L Q Wang ◽  
G H Zhu
Keyword(s):  
Pressure Vessel ◽  
Accurate Method ◽  
Pressure Vessels ◽  
Friction Model ◽  
Interfacial Friction ◽  
Division 1 ◽  
Helical Winding ◽  
Section Viii ◽  
Flat Steel ◽  
Steel Ribbon

Flat steel ribbon wound pressure vessels have been adopted by the ASME Boiler and Pressure Vessel Code, Section VIII, Division 1 and Division 2. An excellent safety and service record has been built up in the past 34 years. Based on the interfacial friction model proposed by Zheng [1], a more accurate method for predicting the stresses in a flat steel ribbon wound pressure vessel is offered in this paper, taking account of the axial displacement, the change in the helical winding angle, the interfacial friction between ribbon layers and the effect of lamination. Comparison between experimental results of five test vessels with an inside diameter varying from 350 to 1000 mm, four different helical winding angles (18, 24, 27 and 30°), two width—thickness ratios of the ribbon (20 and 22.86) and results of calculation using the stress formulae available demonstrates that the method in this paper is more accurate and that interfacial friction gives a marked strengthening contribution to the axial strength of the vessel.

Sign in / Sign up

Export Citation Format

Share Document