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.

Thermal Analysis of Cooling System in a Gas Turbine Transition Piece

2011 ◽  
Author(s):  
Jun Su Park ◽  
Namgeon Yun ◽  
Hokyu Moon ◽  
Kyung Min Kim ◽  
Sin-Ho Kang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Thermal Stresses ◽  
Cooling System ◽  
Structural Information ◽  
Thermal Analyses ◽  
Thermal Design ◽  
Transfer Coefficients ◽  
Transition Piece ◽  
Inlet Conditions

This paper presents thermal analyses of the cooling system of a transition piece, which is one of the primary hot components in a gas turbine engine. The thermal analyses include heat transfer distributions induced by heat and fluid flow, temperature, and thermal stresses. The purpose of this study is to provide basic thermal and structural information on transition piece, to facilitate their maintenance and repair. The study is carried out primarily by numerical methods, using the commercial software, Fluent and ANSYS. First, the combustion field in a combustion liner with nine fuel nozzles is analyzed to determine the inlet conditions of a transition piece. Using the results of this analysis, pressure distributions inside a transition piece are calculated. The outside of the transition piece in a dump diffuser system is also analyzed. Information on the pressure differences is then used to obtain data on cooling channel flow (one of the methods for cooling a transition piece). The cooling channels have exit holes that function as film-cooling holes. Thermal and flow analyses are carried out on the inside of a film-cooled transition piece. The results are used to investigate the adjacent temperatures and wall heat transfer coefficients inside the transition piece. Overall temperature and thermal stress distributions of the transition piece are obtained. These results will provide a direction to improve thermal design of transition piece.

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

Metallurgical Secondary Cooling of Continuous Casting Based on Neural Network Adaptive System Design of Water Distribution

2014 ◽  
Vol 926-930 ◽  
pp. 802-805
Author(s):  
Jun Li Jia ◽  
Jin Hong Zhang ◽  
Guo Zhen Wang
Keyword(s):  
Heat Transfer ◽  
Continuous Casting ◽  
Water Distribution ◽  
Cooling System ◽  
Control Level ◽  
Cooling Water ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Secondary Cooling ◽  
Water Control

Efficient secondary cooling water control level slab continuous casting process and quality are closely related. Casting solidification heat transfer model is the basis of process control and optimization, heat transfer model based on determining the secondary cooling system is the most widely used method for casting production process can be simulated. However, when considering the many factors affecting the production and input conditions change significantly, real-time and strain of this method is not guaranteed. Therefore, the artificial intelligence optimization algorithms such as genetic algorithms, neural networks, fuzzy controllers, introducing continuous casting secondary cooling water distribution and dynamics of optimal control methods, the rational allocation of caster secondary cooling water and dynamic control is important.

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.

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.

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.

On Development of a Semi-Mechanistic Wall Boiling Model

2013 ◽  
Author(s):  
Saurish Das ◽  
Hemant Punekar
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Thermal Stresses ◽  
Cooling System ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Wall Heat Transfer ◽  
Cooling Systems ◽  
Transfer Phenomenon

In modern cooling systems the requirement of higher performance demands highest possible heat transfer rates, which can be achieved by controlled nucleate boiling. Boiling based cooling systems are gaining attention in several engineering applications as a potential replacement of conventional single-phase cooling system. Although the controlled nucleate boiling enhances the heat transfer, uncontrolled boiling may lead to Dry Out situation, adversely affecting the cooling performance and may also cause mechanical damage due to high thermal stresses. Designing boiling based cooling systems requires a modeling approach based on detailed fundamental understanding of this complex two-phase heat and mass transfer phenomenon. Such models can help analyze different cooling systems, detect potential design flaws and carry out design optimization. In the present work a new semi-mechanistic wall boiling model is developed within commercial CFD solver ANSYS FLUENT. A phase change mechanism and wall heat transfer augmentation due to nucleate boiling are implemented in mixture multiphase flow framework. The phase change phenomenon is modeled using mechanistic evaporation-condensation model. Enhancement of wall heat transfer due to nucleate boiling is captured using 1D empirical correlation, modified for 3D CFD environment. A new method is proposed to calculate the local suppression of nucleate boiling based on the flow velocity, and hence this model can be applied to any complex shaped coolant passage. For different wall superheat, the wall heat fluxes predicted by the present model are validated against experimental data, in which 50-50 volume mixture of aqueous ethylene glycol (a typical anti-freeze coolant mixture) is used as working fluid. The validation study is performed in ducts of different sizes and shapes with different inlet velocities, inlet sub-cooling and operating pressures. The results are in good agreement with the experiments. This model is applied to a typical automobile Exhaust Gas Recirculation (EGR) system to study boiling heat transfer phenomenon and the results are presented.

Analysis on Factors Influencing and Numerical Simulation of Hot Stamping Mold Cooling System

2014 ◽  
Vol 644-650 ◽  
pp. 16-20
Author(s):  
Hong Mei Yang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Cooling System ◽  
Hot Stamping ◽  
Cooling Water ◽  
Factors Affecting ◽  
Stamping Die ◽  
Factors Influencing ◽  
Main Factors ◽  
And Performance

Cooling system is an important component of hot stamping dies, directly affects the quality and performance of the product. This article studies the work of hot stamping die process variation in temperature and heat transfer methods, analyzes the main factors affecting the cooling effect, and the use of numerical simulation of the flow of cooling water to simulate the state, and proposed rationalization proposals.

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.

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