Observation of Impact of Progressive Cooling System on Temperature Field Distributions on Surfaces of Injection Moulded Plastic Parts

2015 ◽  
Vol 669 ◽  
pp. 19-28
Author(s):  
Martin Seidl ◽  
Jiří Bobek ◽  
Petr Lenfeld ◽  
Jiří Habr ◽  
Luboš Bĕhálek ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Technology Implementation ◽  
Complex Geometry ◽  
Cooling System ◽  
Technological Parameters ◽  
Cooling Method ◽  
Heat Quantity ◽  
Conventional Cooling ◽  
Plastic Parts

Cooling the injection moulds with using of liquid CO2 is rated among progressive and innovative tempering systems nowadays. In the ideal case this cooling method is chosen in combination with conventional drilled or milled tempering channels where the heat transfer medium flows. These wide-spread ways of cooling are not very often effective enough and they do not provide required accuracy of heat transfer control during production by injection moulding technology. Implementation of capillary tubes that bring the liquid CO2 to critical zones enables local increasing of heat transfer. Regulation of liquid CO2 amount that is injected into mould enables removal of required heat quantity in a very short time period. In this way the homogenous rate of part cooling can be achieved which is very difficult when producing the parts with complex geometry or with combination of various wall thickness. The final mechanical and physical properties of moulded parts accrue from properties of polymer material, part design and used technological parameters. This article deals with evaluation of technological parameters, concretely the cooling parameters of both the conventional cooling method and the system utilizing the cooling potential of liquid CO2. The analysis is focused on observation of temperature field distribution on injected part surfaces.

ANALYSIS OF METHODS FOR CALCULATING HEAT TRANSFER IN THERMOELECTRIC COOLING SYSTEMS FOR HEAT-STRESSED ELEMENTS

2021 ◽  
pp. 21-31
Author(s):  
С.В. Бородкин ◽  
А.В. Иванов ◽  
И.Л. Батаронов ◽  
А.В. Кретинин
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling System ◽  
Average Heat Transfer Coefficient ◽  
The Finite Element Method ◽  
Differential Heat ◽  
Average Heat ◽  
Principal Possibility

На основе уравнений теплопереноса в движущейся среде и соотношений теплопередачи в термоэлектрическом охладителе приведен сравнительный анализ методик расчета поля температуры в теплонапряженном элементе. Рассмотрены методики на основе: 1) теплового баланса, 2) среднего коэффициента теплоотдачи, 3) дифференциального коэффициента теплоотдачи, 4) прямого расчета в рамках метода конечных элементов. Установлено, что первые две методики не дают адекватного распределения поля температур, но могут быть полезны для определения принципиальной возможности заданного охлаждения с использованием термоэлектрических элементов. Последние две методики позволяют корректно рассчитать температурное поле, но для использования третьей методики необходим дифференциальный коэффициент теплоотдачи, который может быть найден из расчета по четвертой методике. Сделан вывод о необходимости комбинированного использования методик в общем случае. Методы теплового баланса и среднего коэффициента теплоотдачи позволяют определить принципиальную возможность использования термоэлектрического охлаждения конкретного теплонапряженного элемента (ТЭ). Реальные параметры системы охлаждения должны определяться в рамках комбинации методов дифференциального коэффициента теплоотдачи и конечных элементов (МКЭ). Первый из них позволяет определить теплонапряженные области и рассчитать параметры системы охлаждения, которые обеспечивают тепловую разгрузку этих областей. Второй метод используется для проведения численных экспериментов по определению коэффициента теплоотдачи реальной конструкции The article presents on the basis of the equations of heat transfer in a moving medium and the relations of heat transfer in a thermoelectric cooler, a comparative analysis of methods for calculating the temperature field in a heat-stressed element. We considered methods based on: 1) heat balance, 2) average heat transfer coefficient, 3) differential heat transfer coefficient, 4) direct calculation using the finite element method. We established that the first two methods do not provide an adequate distribution of the temperature field but can be useful for determining the principal possibility of a given cooling using thermoelectric elements. The last two methods allow us to correctly calculate the temperature field; but to use the third method, we need a differential heat transfer coefficient, which can be found from the calculation using the fourth method. We made a conclusion about the need for combined use of methods in a general case. The methods of thermal balance and average heat transfer coefficient allow us to determine the principal possibility of using thermoelectric cooling of a specific heat-stressed element. The actual parameters of the cooling system should be determined using a combination of the differential heat transfer coefficient and the finite element method. The first of them allows us to determine the heat-stressed areas and calculate the parameters of the cooling system that provide thermal discharge of these areas. The second method is used to perform numerical experiments to determine the heat transfer coefficient of a real structure

scholarly journals Numerical Assessment of Heat Transfer and Entropy Generation of a Porous Metal Heat Sink for Electronic Cooling Applications

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3851
Author(s):  
Hamed Rasam ◽  
Prosun Roy ◽  
Laura Savoldi ◽  
Shabnam Ghahremanian
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Entropy Generation ◽  
Heat Sink ◽  
Cooling System ◽  
Solid Phase ◽  
Porous Metal ◽  
Electronic Equipment ◽  
Bejan Number ◽  
Pore Density

In the present study, the thermal performance of an electronic equipment cooling system is investigated. The heat sink used in the current cooling system consists of a porous channel with a rectangular cross-section that is assumed to be connected directly to the hot surface of an electronic device. In this modeling, a fully developed flow assumption is used. The Darcy–Brinkman model was used to determine the fluid flow field. Since using the local thermal equilibrium (LTE) model may provide results affected by the error in metal foams, in the present research, an attempt has first been made to examine the validity range of this model. The local thermal non-equilibrium (LTNE) model taking into account the viscous dissipation effect was then used to determine the temperature field. To validate the numerical solution, the computed results were compared with other studies, and an acceptable agreement was observed. Analysis of the temperature field shows that if the fluid–solid-phase thermal conductivity ratio is 1 or the Biot number has a large value, the difference between the temperature of the solid phase and the fluid phase decreases. Moreover, the effect of important hydrodynamic parameters and the porous medium characteristics on the field of hydrodynamic, heat, and entropy generation was studied. Velocity field analysis shows that increasing the pore density and reducing the porosity cause an increase in the shear stress on the walls. By analyzing the entropy generation, it can be found that the irreversibility of heat transfer has a significant contribution to the total irreversibility, leading to a Bejan number close to 1. As a guideline for the design of a porous metal heat sink for electronic equipment, the use of porous media with low porosity reduces the total thermal resistance and improves heat transfer, reducing the total irreversibility and the Bejan number. Moreover, the increasing of pore density increases the specific porous surface; consequently, it reduces the total irreversibility and Bejan number and improves the heat transfer.

Two Phase Flow Simulation for Nucleate Boiling Heat Transfer Calculation in Waterjacket of Diesel Engine

2011 ◽  
Author(s):  
Arash Mohammadi ◽  
Hossein Hashemi ◽  
Ali Jazayeri ◽  
Mahdi Ahmadi
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Diesel Engine ◽  
Transfer Coefficient ◽  
Cylinder Head ◽  
Boiling Heat Transfer ◽  
Cooling System ◽  
Nucleate Boiling ◽  
Two Phase ◽  
Phase Mixture

Basic understanding of the process of coolant heat transfer inside an engine is an indispensable prerequisite to devise an infallible cooling strategy. Coolant flow and its heat transfer affect the cooling efficiency, thermal load of heated components, and thermal efficiency of a diesel engine. An efficient approach to study cooling system for diesel engine is a 3D computational fluid dynamics (CFD) calculation for coolant jacket. Therefore, computer simulation can analyze and consequently optimize cooling system performance, including complex cooling jacket. In this paper a computational model for boiling heat transfer based on two-phase Mixture model flow is established. Furthermore, the phenomenon of nucleate boiling, its mathematical modeling, and its effect on heat transfer is discussed. Besides, the static, total and absolute pressure, velocity and stream lines of the flow field, heat flux, heat transfer coefficient and volume fraction of vapor distribution in the coolant jacket of a four-cylinder diesel engine is computed. Also, comparison between experimental equation (Pflaum/Mollenhauer) and two-phase Mixture model for boiling hat transfer coefficient is done and good agreement is seen. In conclusion, it is observed that at high operating temperatures, nucleate boiling occurs in regions around the exhaust port. Numerical simulation of boiling heat transfer process of cooling water jacket and temperature field in the cylinder head of the diesel engine is compared with the data measured on the engine test bench. The calculated results indicate that this method can reflect the impact of boiling heat transfer on water jacket rather accurate. Therefore, this method is benefit to improve the computational precision in the temperature field computation of a cylinder head.

Design and Optimization of Conformal Cooling System of an Injection Molding Chimney

2016 ◽  
Vol 850 ◽  
pp. 679-686
Author(s):  
He Li ◽  
Yi Mei ◽  
Bo Lin ◽  
Hua Qiang Xiao
Keyword(s):  
Temperature Field ◽  
Cooling System ◽  
Transfer Model ◽  
Analysis Method ◽  
Range Analysis ◽  
Straight Pipe ◽  
Cooling Systems ◽  
Conformal Cooling ◽  
Design And Optimization ◽  
Plastic Parts

Cooling system is important in the quality and the efficiency of forming plastic parts. The heat transfer model for conformal chimney cavity and straight pipe cooling system was developed employing thermal analysis module of UG software. The temperature field distributions of two cavities were analyzed. The differences in chimney forming warping deformations, shrinkage and freeze times for the two types of cooling systems were analyzed quantitatively by Moldflow software. The results showed that the temperature field distribution of the conformal cooling system was more homogeneous and the forming quality and efficiency of molding for the plastic parts was better. Finally, the cooling system parameters were optimized through orthogonal test and range analysis method.

Investigation of Machinability in Minimum Quantity Lubrication Milling of GH4169 Aerospace Superalloy

2010 ◽  
Vol 34-35 ◽  
pp. 666-670 ◽  
Author(s):  
Song Mei Yuan ◽  
Lu Tao Yan ◽  
Wei Dong Liu ◽  
Qiang Liu
Keyword(s):  
Cutting Force ◽  
Surface Finish ◽  
Cooling System ◽  
Minimum Quantity Lubrication ◽  
Cutting Parameters ◽  
Depth Of Cut ◽  
Minimum Quantity ◽  
Cooling Method ◽  
Conventional Cooling ◽  
Cooling Air

Due to environmental concerns and the coming legislations, pollution-free and eco-friendly minimum quantity lubrication (MQL) technology has become focus of attention in manufacture field. The MQL and cooling system in this work has been designed, fabricated and used. The cutting performance of MQL with cooling air compare with the conventional cooling method in milling of GH4169 aerospace superalloy is evaluated based on analysis of cutting force and surface finish. The effect of cutting parameters (depth of cut, feed rate) on machining performances is analyzed. The experimental results show that, the application of MQL and cooling air brings about a lower cutting force, better surface finish compared to conventional coolant environment.

Impact of Innovative Cooling System on Mechanical Properties of Moulded Parts

2016 ◽  
Vol 368 ◽  
pp. 49-52
Author(s):  
Jiří Habr ◽  
Martin Seidl ◽  
Jiří Bobek
Keyword(s):  
Heat Transfer ◽  
Mechanical Properties ◽  
Cooling System ◽  
Flexural Modulus ◽  
Temperature Fields ◽  
Part Surface ◽  
Spot Cooling ◽  
Conventional Cooling ◽  
Heat Processes ◽  
The Impact

This article deals with the impact evaluation of utilization of innovative cooling system exploiting liquid carbon dioxide injected into injection mould. Process of heat transfer from the polymeric melt and final part solidification has a direct impact on creation of morphology structure of semi-crystalline thermoplastic materials and their ultimate mechanical properties. Usually the heat processes in the production tools are controlled by tempering channels where heat transfer medium circulates (oil, water tec.). This conventional way of cooling has some limitations that cause an uneven distribution of temperature fields on the part surface. Spot cooling system is one of unconventional cooling ways that increase the uniformity of temperature fields distribution on the part surface. This system utilizes the cooling potential of liquid CO2. For the purpose of this study the special shaped insert was designed that was modified both for conventional cooling and for spot cooling system. Flexural modulus very responsively reflects the changes of morphology structure formed by different cooling progressions of the plastic melt and was chosen as an evaluating criterion.

Numerical Analysis and Experimental Assessment of the Cylinder Temperature in a Reciprocating Compressor

2015 ◽  
Author(s):  
Francesco Balduzzi ◽  
Andrea Tanganelli ◽  
Giovanni Ferrara ◽  
Alberto Babbini ◽  
Riccardo Maleci
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Numerical Analysis ◽  
Thermal Stresses ◽  
Thermal State ◽  
Cooling System ◽  
Cooling Water ◽  
Actual Condition ◽  
Reciprocating Compressor ◽  
Compressor Cylinder

Accurate evaluation of the thermal deformation is important to the analysis of reciprocating compressors since the induced deformations are responsible of the thermal stresses on the cylinder. The cylinder body experiences a non-uniform temperature distribution, with the presence of hot and cold spots, creating a bending strain on the structure. A cylinder cooling system is designed to control the uniformity of the temperature field and to reduce the fresh gas heating due to a hot cylinder body, improving the volumetric efficiency. Due to the difficulties associated with obtaining detailed data on the heat transfer processes by experimental means, a more and more important role is played by numerical analysis in reciprocating compressor design. This paper shows the capability of a conjugate heat transfer (CHT) simulation for a double-acting reciprocating compressor cylinder in accurately predicting both the thermal state of the compressor cylinder and the temperature field of the cooling water. The results of the three-dimensional simulations of the water-circuit flow field and the thermal conduction inside the solid metal were compared to temperature measurements collected on a dedicated test bench for both the coolant and the metal structure. Satisfactory agreement was obtained between the experimental data and the numerical computations. In addition, three different modifications for the CHT model were introduced in order to obtain a better match with the experimental results. The suitability of using the CHT simulation as an efficient tool for replicating the actual condition of the reciprocating compressor was analyzed and discussed.

scholarly journals High Potential of Magnet on the Performance of Dual Piezoelectric Fans in Electronics Cooling System

2018 ◽  
Vol 10 (2) ◽  
pp. 469 ◽  
Author(s):  
Abdul Razak Fadhilah ◽  
Robiah Ahmad ◽  
Sarip Shamsul
Keyword(s):  
Heat Transfer ◽  
Magnetic Force ◽  
Cooling System ◽  
Electronics Cooling ◽  
Total Amplitude ◽  
System A ◽  
Cooling Method ◽  
Optimization Parameters ◽  
Better Than ◽  
Good Agreement

Recently, piezoelectric fan has gained attention as potential active cooling method for electronics devices. Even though the piezoelectric requires high voltage, there are findings to overcome the shortcomings. Adding on a magnet at the tip of the piezoelectric fan to activate other magnetic passive fans is one of the methods to increase the total amplitude generated by the fans. This paper will discuss on the performance of integrated piezoelectric fan with passive fans (later refer to magnetic fans) to enhance the heat transfer in cooling system. A repulsive force produced by the magnets will cause the magnetic blades to oscillate together with the piezoelectric fan. The paper will focus on the optimization parameters of the magnets for selected dimension of piezoelectric fan. The parameters under investigation are the position of the magnet on the piezoelectric fan, number of magnets on each blades and orientation of blades with respect to adjacent blade. Results show that the magnet at middle location of extensive blade with double magnets generate the largest amplitude, 80% better than fan without magnet and for dual integrated piezoelectric fan with magnetic fan, radial orientation gives better result by 25%. By increasing the total amplitude using magnetic force, power consumption can be reduced while the heat transfer performance can be enhanced. it shows a good agreement for positive heat transfer and thermal resistance improvement compared to natural convection.

Development of Inherently Safe Technologies for Large Scale BWRs: (3) Infinite-Time Air-Cooling System

2014 ◽  
Author(s):  
Akinori Tamura ◽  
Toshinori Kawamura ◽  
Naoyuki Ishida ◽  
Kazuaki Kitou
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Performance ◽  
Cooling System ◽  
Natural Circulation ◽  
Air Cooling ◽  
Transfer Performance ◽  
Infinite Time ◽  
Air Cooling System ◽  
Heat Quantity

To address long-term station black outs, which occurred at the Fukushima Nuclear Power Station, we have been developing the infinite-time air-cooling system which operates without electricity by a natural circulation loop. The air-cooling heat exchanger, which is located outside the primary containment vessel of a reactor, transfers the decay heat to the atmosphere by natural circulation resulting from the density difference of the air. Improvement in the heat-transfer performance of air-cooling is a key technology in the development of the infinite-time air-cooling system. In this paper, we developed the air-cooling enhancing technology for the infinite-time air-cooling system by using a micro-fabrication surface, turbulence-enhancing structures, and heat-transfer fins. To evaluate the performance of this air-cooling enhancing technology, we conducted a heat exchange test using an element test apparatus. A single tube of the air-cooling heat exchanger, which includes a sheath heater and thermo-couples, was used. The air flow outside the tube and the heat quantity were respectively controlled using an air-compressor and the sheath heater. The heat-transfer performance was calculated from the heat-quantity and temperature difference measured using thermo-couples. The developed air-cooling enhancing technology demonstrated superior heat-transfer performance in this test. The heat-transfer performance increased approximately 100 % with this technology compared with a bare pipe. From these experimental results, we confirmed good feasibility for implementing the infinite-time air-cooling system.

A Computer-Aided Cooling-Line Design System for Injection Molds

1990 ◽  
Vol 112 (2) ◽  
pp. 161-167 ◽  
Author(s):  
L. S. Turng ◽  
K. K. Wang
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Cooling System ◽  
Transient Heat Conduction ◽  
Heat Transfer Process ◽  
Design System ◽  
Cavity Surface ◽  
Transient Temperature ◽  
Numerical Predictions ◽  
Line Design

This paper presents a methodology for analyzing the heat-transfer process during the injection molding of plastics as an aid to mold design. A numerical scheme using the Boundary Element Method (BEM) with “zonal” approach has been developed to solve the quasi-steady temperature field and its normal derivative over the entire surface of the mold plates including the cavity wall as well as parting surface. In order to obtain a solution for the temperature field, a cycle-averaged heat-transfer coefficient is introduced from a transient heat-conduction analysis and applied as the boundary condition at the cavity surface. The numerical predictions as compared with the experimental data have shown that the cycle-averaged solution used in this study gives a reasonable representation of the transient temperature variation over the cavity surface. Based on the numerical predictions, the mold designer will be able to design a proper cooling-system for a mold to achieve better part quality and high productivity through more uniform cooling and shorter cycle time, respectively.

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