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.

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

Analytical Modeling of Temperature Distribution in Interposer-Based Microelectronic Systems

2013 ◽  
Author(s):  
Leila Choobineh ◽  
Dereje Agonafer ◽  
Ankur Jain
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Analytical Modeling ◽  
Three Dimensional ◽  
Heat Transfer Process ◽  
Thermal Design ◽  
Research Attention ◽  
On Chip

Heterogeneous integration in microelectronic systems using interposer technology has attracted significant research attention in the past few years. Interposer technology is based on stacking of several heterogeneous chips on a common carrier substrate, also referred to as the interposer. Compared to other technologies such as System-on-Chip (SoC) or System-in-Package (SiP), interposer-based integration offers several technological advantages. However, the thermal management of an interposer-based system is not well understood. The presence of multiple heat sources in various die and the interposer itself needs to be accounted for in any effective thermal model. While a finite-element based simulation may provide a reasonable temperature prediction tool, an analytical solution is highly desirable for understanding the fundamentals of the heat transfer process in interposers. In this paper, we describe our recent work on analytical modeling of heat transfer in interposer-based microelectronic systems. The basic governing energy conservation equations are solved to derive analytical expressions for the temperature distribution in an interposer-based microelectronic system. These solutions are combined with an iterative approach to provide the three-dimensional temperature field in an interposer. Results are in excellent agreement with finite-element solutions. The analytical model is utilized to study the effect of various parameters on the temperature field in an interposer system. Results from this work may be helpful in the thermal design of microelectronic systems containing interposers.

Simulation to the Temperature Field for Continuous Casting Billet during Direct Rolling of Free-Heating

2014 ◽  
Vol 941-944 ◽  
pp. 1890-1894
Author(s):  
Guang Zheng Luo ◽  
Xin Liu ◽  
Ying Zhi ◽  
Xiang Hua Liu
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Temperature Field ◽  
Continuous Casting ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Direct Rolling ◽  
Cutting Point ◽  
Continuous Casting Billet

The temperature field of continuous casting billet (CC-billet) is important to carry out the research on direct rolling of free-heating (DROF). The solidification and the heat transfer process of CC-billet from crystallizer to cutting point were studied by finite element method (FEM).The casting speed was improved in order to get reasonable temperature field during DROF.

HP Vane Aerodynamics and Heat Transfer in the Presence of Aggressive Inlet Swirl

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Imran Qureshi ◽  
Andy D. Smith ◽  
Thomas Povey
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Three Dimensional ◽  
Leading Edge ◽  
Good Deal ◽  
Vortex Center ◽  
Research Facility ◽  
Lean Burn ◽  
Numerical Predictions ◽  
The Impact

Modern lean burn combustors now employ aggressive swirlers to enhance fuel-air mixing and improve flame stability. The flow at combustor exit can therefore have high residual swirl. A good deal of research concerning the flow within the combustor is available in open literature. The impact of swirl on the aerodynamic and heat transfer characteristics of an HP turbine stage is not well understood, however. A combustor swirl simulator has been designed and commissioned in the Oxford Turbine Research Facility (OTRF), previously located at QinetiQ, Farnborough UK. The swirl simulator is capable of generating an engine-representative combustor exit swirl pattern. At the turbine inlet plane, yaw and pitch angles of over ±40 deg have been simulated. The turbine research facility used for the study is an engine scale, short duration, rotating transonic turbine, in which the nondimensional parameters for aerodynamics and heat transfer are matched to engine conditions. The research turbine was the unshrouded MT1 design. By design, the center of the vortex from the swirl simulator can be clocked to any circumferential position with respect to HP vane, and the vortex-to-vane count ratio is 1:2. For the current investigation, the clocking position was such that the vortex center was aligned with the vane leading edge (every second vane). Both the aligned vane and the adjacent vane were characterized. This paper presents measurements of HP vane surface and end wall heat transfer for the two vane positions. The results are compared with measurements conducted without swirl. The vane surface pressure distributions are also presented. The experimental measurements are compared with full-stage three-dimensional unsteady numerical predictions obtained using the Rolls Royce in-house code Hydra. The aerodynamic and heat transfer characterization presented in this paper is the first of its kind, and it is hoped to give some insight into the significant changes in the vane flow and heat transfer that occur in the current generation of low NOx combustors. The findings not only have implications for the vane aerodynamic design, but also for the cooling system design.

scholarly journals Cooling Process Analysis of a 5-Drum System for Radioactive Waste Processing

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2689
Author(s):  
Alfredo Iranzo ◽  
Francisco Pino ◽  
José Guerra ◽  
Francisco Bernal ◽  
Nicasio García
Keyword(s):  
Heat Transfer ◽  
Radioactive Waste ◽  
Cooling System ◽  
Process Analysis ◽  
Internal Heat ◽  
Maximum Temperature ◽  
Transient Temperature ◽  
Cfd Modelling ◽  
Air Inlet ◽  
Slag Properties

A cooling system design for the processing of radioactive waste drums is investigated in this work, with the objective of providing insights for the determination of the air flow rate required to ensure an acceptable slag temperature (323 K or below) after 5 days. A methodology based on both 3D and 2D axisymmetric Computational Fluid Dynamics (CFD) modelling is developed. Transient temperature distributions within the drums in time and space determined by the heat transfer characteristics are studied in detail. A sensitivity analysis is also carried out assuming different physical properties of the radioactive slag. It was found out that for all variations analyzed, the maximum temperature of slag at the end of five days cooling is below 323 K, where the maximum outlet air temperature for a minimum air inlet velocity of 1 m/s is between 320 K and 323 K depending on the radioactive slag properties. When glass-like radioactive slag properties are assumed, the internal heat conduction within the slag is limiting the overall heat transfer, therefore requiring significantly longer cooling times.

Computation of flow and heat transfer through channels with periodic dimple/protrusion walls using low-Reynolds number turbulence models

2019 ◽  
Vol 29 (3) ◽  
pp. 1178-1207 ◽  
Author(s):  
Mohammad Fazli ◽  
Mehrdad Raisee
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Correction Term ◽  
Turbine Blades ◽  
Turbulence Models ◽  
Internal Cooling ◽  
Recirculation Bubble ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Numerical Predictions

PurposeThis paper aims to predict turbulent flow and heat transfer through different channels with periodic dimple/protrusion walls. More specifically, the performance of various low-Rek-ε turbulence models in prediction of local heat transfer coefficient is evaluated.Design/methodology/approachThree low-Re numberk-εturbulence models (the zonalk-ε, the lineark-εand the nonlineark-ε) are used. Computations are performed for three geometries, namely, a channel with a single dimpled wall, a channel with double dimpled walls and a channel with a single dimple/protrusion wall. The predictions are obtained using an in house finite volume code.FindingsThe numerical predictions indicate that the nonlineark-εmodel predicts a larger recirculation bubble inside the dimple with stronger impingement and upwash flow than the zonal and lineark-εmodels. The heat transfer results show that the zonalk-εmodel returns weak thermal predictions in all test cases in comparison to other turbulence models. Use of the lineark-εmodel leads to improvement in heat transfer predictions inside the dimples and their back rim. However, the most accurate thermal predictions are obtained via the nonlineark-εmodel. As expected, the replacement of the algebraic length-scale correction term with the differential version improves the heat transfer predictions of both linear and nonlineark-εmodels.Originality/valueThe most reliable turbulence model of the current study (i.e. nonlineark-εmodel) may be used for design and optimization of various thermal systems using dimples for heat transfer enhancement (e.g. heat exchangers and internal cooling system of gas turbine blades).

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.

scholarly journals Study of the fire dynamics in a burning car and analysis of the possibilities for transfer of fire to a nearby vehicle

2019 ◽  
Vol 112 ◽  
pp. 01015 ◽  
Author(s):  
Angel Terziev
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Infrared Camera ◽  
Heat Transfer Process ◽  
Engine Compartment ◽  
Fire Dynamics ◽  
Scale Experiment ◽  
Clear Change ◽  
Specialized Measuring ◽  
Ignition Zone

A full scale experiment was carried out on the process of vehicle combustion and the ignition of an adjacent one. For this purpose, specialized measuring equipment (thermocouples and infrared camera) is used to determine the temperature field of the burning car and nearby vehicle. The burning car has 16 thermocouples mounted on it and one thermocouple mounted on the adjacent car in order to examine the heat transfer process. The temperature field between cars at different points of time is detected by an infrared camera, with a clear change in the temperature gradient in the presence of wind. It is one of the main reasons for the increased momentum of heat transfer. The research shows that with the available combustible load of the car (2,1 MW or around the average for the currently produced cars), the ignition of the neighbouring vehicle is expected around 14 minutes after the ignition of the main vehicle, with the ignition zone being in the engine compartment. Important information was obtained for both the dynamics of the burning vehicle and the temperature field between the two cars.

Research on Heat-Transfer Process of the Radiant Ceiling Cooling System

2012 ◽  
Vol 512-515 ◽  
pp. 2171-2174 ◽  
Author(s):  
Quan Ying Yan ◽  
Ran Huo ◽  
Li Li Jin
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Cooling System ◽  
Numerical Models ◽  
Cooling Water ◽  
Lower Surface ◽  
Cooling Capacity ◽  
Heat Transfer Process ◽  
Lower Surface Temperature ◽  
Selection Of

Physical and numerical models of the radiant ceiling cooling system were built and numerically simulated. The results showed that the lower the temperature of cooling water is, the lower surface temperature the ceiling has, and the bigger the cooling capacity is. The bigger the depth of tubes is, the higher the surface temperature and the smaller the cooling capacity. The differences are not evident. The bigger the distance of tubes is, the bigger the surface temperature is and the smaller the cooling capacity is. The diameter of tubes has a few influences on the surface temperature and the cooling capacity. Results in this paper can provide basis and guide for the design of the project, the selection of parameters and the feasibility of the system.

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.

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