Plastic pipe solidification in extrusion

2018 ◽  
Vol 38 (6) ◽  
pp. 591-603
Author(s):  
Pongthep Poungthong ◽  
Chanyut Kolitawong ◽  
Chaimongkol Saengow ◽  
Alan Jeffrey Giacomin
Keyword(s):  
Residual Stress ◽  
Cooling System ◽  
Outer Wall ◽  
Solidification Time ◽  
Solidification Temperature ◽  
Pipe Surface ◽  
Plastic Pipe ◽  
External Cooling ◽  
Wall Boundary Conditions ◽  
Pipe Extrusion

AbstractIn plastic pipe extrusion, hot molten extrudate emerges from an annular. This highly viscous liquid is then cooled and solidified, calledquenching, in a quench tank. In this paper, we focus on the external cooling system. We use an adiabatic inner wall and differing outer wall boundary conditions: isothermal and convection. The solid-liquid interface, at the solidification temperature, moves inward with deceleration. We adimensionalize the energy balance and solve for the interface speed in terms of the solidifcation coefficient,λ. We arrive at the exact solutions for the evolving solidified thickness. Finally, we use the residual stress model developed by Jansen [Int. Polym. Proc. 1994, 9, 82–89]. to predict the compressive residual stress at the outer pipe surface. Our new exact solution for the solidification time agrees well with the data from the plastic pipe industry. The goals of this paper are to help plastics engineers calculate the solidification time, to design the cooling chamber and to predict the residual quenching stress.

Elimination of Sag in Plastic Pipe Extrusion

1992 ◽  
Vol 7 (2) ◽  
pp. 140-143 ◽  
Author(s):  
D. N. Githuku ◽  
A. J. Giacomin
Keyword(s):  
Plastic Pipe ◽  
Pipe Extrusion

An Unsteady Analysis on Thermal Stratification in the SCS Piping Branched Off the RCS Piping

2003 ◽  
Author(s):  
Kwang-Chu Kim ◽  
Man-Heung Park ◽  
Hag-Ki Youm ◽  
Sun-Ki Lee ◽  
Tae-Ryong Kim ◽  
...  
Keyword(s):  
Temperature Difference ◽  
Thermal Stratification ◽  
Nuclear Power ◽  
Cooling System ◽  
Numerical Study ◽  
Outer Wall ◽  
Maximum Temperature ◽  
Rear Side ◽  
Maximum Temperature Difference ◽  
Starting Point

A numerical study is performed to estimate on an unsteady thermal stratification phenomenon in the Shutdown Cooling System (SCS) piping branched off the Reactor Coolant System (RCS) piping of Nuclear Power Plant. In the results, turbulent penetration reaches to the 1st isolation valve. At 500sec, the maximum temperature difference between top and bottom inner wall in piping is observed at the starting point of horizontal piping passing elbow. The temperature of coolant in the rear side of the 1st isolation valve disk is very slowly increased and the inflection point in temperature difference curve for time is observed at 2700sec. At the beginning of turbulent penetration from RCS piping, the fast inflow generates the higher temperature for the inner wall than the outer wall in the SCS piping. In the case the hot-leg injection piping and the drain piping are connected to the SCS piping, the effect of thermal stratification in the SCS piping is decreased due to an increase of heat loss compared with no connection case. The hot-leg injection piping affected by turbulent penetration from the SCS piping has a severe temperature difference that exceeds criterion temperature stated in reference. But the drain piping located in the rear compared with the hot-leg injection piping shows a tiny temperature difference. In a viewpoint of designer, for the purpose of decreasing the thermal stratification effect, it is necessary to increase the length of vertical piping in the SCS piping, and to move the position of the hot-leg injection piping backward.

A Study of Convective Heat Transfer and Pressure Drop Phenomena in Curved Microchannels

2010 ◽  
Author(s):  
Heng-Chih Tang ◽  
Tien-Chien Jen ◽  
Yi-Hsin Yen ◽  
Jyh-Tong Teng
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Cooling System ◽  
Outer Wall ◽  
Flow Patterns ◽  
Hydraulic Diameter ◽  
Main Stream ◽  
Dean Number

The research conducted in this paper was based on numerical simulation analysis that investigated the relationships between convective heat transfer and pressure drops and the flow patterns between conventional straight channels and curved microchannels. The main goal is to thoroughly investigate thermo-fluidic phenomena in curved microchannels and to determine the optimal design for the curved microchannel cooling system. Commercial numerical software (ESI-CFD) was used to simulate all cases studied in this paper. The computer simulated results were compared with actual experimental results to evaluate its accuracy. Six cases of different dimensions were studied. Results obtained from this study showed that when the dimensions of curved microchannels are smaller than 40 μm in height, conventional macro fluidic theory can still be used, since the numerically simulated results are in good agreement (<6% difference) with those obtained experimentally. Hydraulic diameter is the factor affects the pressure drop. Larger hydraulic diameter causes smaller pressure drop while smaller hydraulic diameter results in higher pressure drop. Secondary flow patterns and Nusselt numbers are also illustrated in this paper. When the Dean number is lower than 400, the pressure drop of fluid in 40 μm height models is similar to that found in straight microchannels. For the velocity profiles in the curved microchannels, the main stream is at the center of the curved microchannel first. But it is gradually offsets to the outer wall when the mass flow rates increases. The centrifugal force due to the curve geometry is the main reason that results in the shifting of the main flow toward the outer wall of the microchannel.

Transient Thermal Analyses of Midwall Cooling and External Cooling Methods for a Gun Barrel

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Avanish Mishra ◽  
Amer Hameed ◽  
Bryan Lawton
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Thermal Analyses ◽  
Temperature History ◽  
Fe Model ◽  
Gun Barrel ◽  
External Cooling ◽  
Transient Thermal ◽  
Cooling Methods ◽  
Simulation Scheme

Liquid cooling methods are often used for thermal management of a large caliber gun barrel. In this work, transient thermal analyses of midwall-cooled and externally cooled gun barrels were performed. At first, a novel simulation scheme was developed for the computation of the gun barrel temperature history (temperature variation over time), and its experimental validation was performed. In the computational scheme an internal ballistics code, GUNTEMP8.EXE, was developed to simulate the total heat transfer per cycle for the given ammunition parameters. Subsequently, a finite element (FE) model of the barrel was developed in ANSYS 11.0. Heat transfer to the barrel was approximated by an exponentially decaying heat flux. The FE model was solved to compute for barrel temperature history. Simulations were performed for a burst of 9 cycles, and the results were found to agree with the experimental measurements. Subsequently, the simulation scheme was extended to analyze a burst of 40 cycles at 10 shots per minute (spm). Three cases were investigated as follows: (1) a naturally cooled gun barrel, (2) a gun barrel with midwall cooling channels, and (3) an externally cooled gun barrel. Natural cooling was found insufficient to prevent cook-off, whereas midwall and external cooling methods were found to eliminate any possibility of it. In the context of a self-propelled howitzer, a midwall-cooled gun barrel connected to an engine cooling system was also analyzed.

Postoperative analgesic effects of an external cooling system and intra-articular bupivacaine/morphine after arthroscopic cruciate ligament surgery

1996 ◽  
Vol 4 (4) ◽  
pp. 200-205 ◽  
Author(s):  
Sveinbjörn Brandsson ◽  
Bengt Rydgren ◽  
Thomas Hedner ◽  
Olof Lundin ◽  
Leif Sward ◽  
...  
Keyword(s):  
Cooling System ◽  
Cruciate Ligament ◽  
Analgesic Effects ◽  
External Cooling

A Technological Effect Modeling on Complex Turbomachinery Applications With an Overset Grid Numerical Method

2013 ◽  
Author(s):  
Gilles Billonnet ◽  
Lionel Castillon ◽  
Jacques Riou ◽  
Gilles Leroy ◽  
André Paillassa
Keyword(s):  
Film Cooling ◽  
Cooling System ◽  
Guide Vane ◽  
Grid Method ◽  
Industrial Test ◽  
Secondary Flows ◽  
Inlet Guide Vane ◽  
Overset Grid ◽  
Overlapping Grids ◽  
Wall Boundary Conditions

The modeling of technological effects on complex turbomachinery flow is described in the paper. The Chimera method based on structured overlapping grids is applied using the ONERA solver elsA. The application of the method on two industrial test cases are presented. The first investigated application is an experimental configuration of a turbine vane with film-cooling. The film cooling system is made up of a very large number of holes. The Chimera method enables simulating the interaction between the cooling jets and the vane flow and improves heat flux prediction compared to simulations modeling cooling flows with wall boundary conditions. The second investigated application is a variable Inlet Guide Vane of an experimental compressor. The application includes the main flow vane, the pivot linking the hub wall with the IGV blade, and the built-in turntable within the shroud which ensures the blade fitting. The benefit of the overset grid method is highlighted by comparisons with computation results obtained on the smooth end-walls. For three different stagger angles (0°, 30° and 60°) the patterns of the secondary flows are presented as well as the comparisons of the calculated flow field with the available experimental data.

scholarly journals Anhydrous Cooling Mode Applied in External cooling Equipment of HVDC Converter

2018 ◽  
Vol 7 (3) ◽  
pp. 149
Author(s):  
Yu-liang WEN ◽  
Guang-wu WANG ◽  
Zhi-min LU ◽  
Jian-ye CHEN
Keyword(s):  
Natural Gas ◽  
Cooling System ◽  
Gas Pipeline ◽  
Cooling Mode ◽  
Long Distance ◽  
Natural Gas Pipeline ◽  
External Cooling ◽  
Operation Process ◽  
In Series ◽  
Air Cooler

Anhydrous Cooling Mode is that it consumes little water in the operation process. This paper made some investigates in the external cooling equipment which is currently applied in the HVDC converter substation. There are some anhydrous cooling modes in the HVDC converter substation. A case of anhydrous cooling mode which air cooler series with the water chiller applied in the long distance natural gas pipeline pressurization was introduced. It is recommended that the cooling system composed of air cooler in series with chilling water will be preferentially chosen as an anhydrous cooling mode applied in the HVDC converter external cooling equipment.

High Temperature Overhung Pumps: Cooling Optimization

2005 ◽  
Author(s):  
M. Cipolla
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Cooling System ◽  
Cooling Water ◽  
Experimental Tests ◽  
Thermal Dissipation ◽  
Lubricating Oil ◽  
Fluid Temperature ◽  
External Cooling ◽  
Set Up

A typical industrial application of high temperature pumps involves handling of fluids up to 400 °C. This is critical for pump bearing housing, where thermal dissipation is not effective due to geometric configuration. Therefore, without any external cooling system, bearings and lubricating oil temperatures can exceed allowable values prescribed by both API 610 Reference Standard [1] and bearing manufacturer [2]. Particularly, for a overhung pump, when pumped fluid temperature is above 200 °C, external cooling system is necessary and water is usually used for this purpose. Consequently, water availability must be taken into account when considering pump’s location, which is particularly difficult in desert areas. From these considerations was the idea to enhance the heat transfer of the pump support, in order to avoid any need of cooling water. The problem has been dealt with numerical analysis and experimental tests. First, we have considered the original support in the most critical situation, the stand-by condition, where no forced convection (fan) is effective. From the results pertaining to currently used support, we have got the hints to improve heat transfer by a full redesign. Finally an experimental validation has been set up. The measures gained allow us to validate hypothesis taken into consideration in the numerical simulation.

Numerical Simulation on Influence of Water-Cooled Stool in the Process of Unidirectional Solidification

2014 ◽  
Vol 936 ◽  
pp. 1317-1322
Author(s):  
Xiao Dong Li ◽  
Ming Gang Shen ◽  
Chao Wu
Keyword(s):  
Numerical Simulation ◽  
Cooling System ◽  
Solidification Process ◽  
Longitudinal Direction ◽  
Algebraic Model ◽  
Unidirectional Solidification ◽  
Air Gap ◽  
Temperature Fields ◽  
Element Analysis ◽  
Solidification Temperature

To strengthen the bottom cooling is one of the key technologies of directionally solidified ingot process. Stool cooling scheme has a significant impact on the solidification process of the ingot. The study optimizes chassis cooling scheme according to the air gap between the ingot and the stool. With multiple sets of cooling system, water-cooled stool makes the basal water cooling adapt to air gap distribution through subregional cooling of different intensity control, and be uniform with it in the longitudinal direction solidification. The paper establishes mathematical model of unidirectional solidified ingot on temperature field of conventional water-cooled stool and improved one respectively. By the aid of finite element analysis method, numerical simulation of 45t ingot with algebraic model is carried out. In order to optimize parameters of ingot unidirectional solidification, temperature fields influenced by conventional water-cooled stool and improved one in the process of unidirectional solidification are simulated. The numerical results show that the optimized chassis cooling can result in the ingot in a longitudinal uniform solidification. The numerical simulation results can provide important reference for the optimization of unidirectional solidification process.

Sign in / Sign up

Export Citation Format

Share Document