Numerical Analysis of the Heat Transfer in Passive Solar Composite Wall Collectors System With Porous Absorber

2007 ◽  
Author(s):  
Wei Chen
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Particle Size ◽  
Temperature Field ◽  
Room Temperature ◽  
Heating System ◽  
Thermal Insulator ◽  
Composite Wall ◽  
Unsteady Numerical Simulation ◽  
Solar Wall

In this paper, heat transfer and flow in the composite solar wall with porous absorber has been studied. The unsteady numerical simulation is employed to analyze the performance of the flow and temperature field in the composite solar wall. The excess heat is stored within the porous absorber during solar radiation and there is stratification in the porous layer. So, the porous absorber works as thermal insulator in a degree when no solar shining is available. The heating characteristic of two types of the composite solar wall with porous absorber has been conducted. The influence of particle size, porosity and porous absorber arrange in the solar composite wall on the heating room temperature is significant. The results show that all these factors should be taken into account for a better design of a heating system.

Thermal Analysis of Porous Media in Passive Solar Composite

2009 ◽  
Author(s):  
Wei Chen
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Thermal Analysis ◽  
Porous Media ◽  
Temperature Field ◽  
Heating System ◽  
Incident Solar Radiation ◽  
Thermal Insulator ◽  
Unsteady Numerical Simulation ◽  
Solar Wall

In this paper, heat transfer and flow in a composite solar wall with porous absorber has been studied. The unsteady numerical simulation is employed to analyze the performance of the flow and temperature field in the composite solar wall. The excess heat is stored in the porous absorber and wall by the incident solar radiation and there is a temperature gradient in the porous layer. So, the porous absorber works as thermal insulator in a degree when no solar shining is available. The influence of the porosity within the porous absorber on the air flow in the porous absorber is significant. The results show that all these factors should be taken into account for a better design of a heating system.

The Characteristics of Porous Solar Wall Heating System with Localized UFAD

2012 ◽  
Vol 178-181 ◽  
pp. 237-243
Author(s):  
Li Ouyang ◽  
Wei Liu
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Saturated Porous Medium ◽  
Flow Characteristics ◽  
Heating System ◽  
Physical Models ◽  
Air Distribution ◽  
Cable System ◽  
Wall Heating ◽  
Solar Wall

In this paper, the physical models of the porous solar wall heating system with localized underfloor air distribution (UFAD) are established. Based on Brinkman-Forchheimer Extended Darcy and energy two-equation models for saturated porous medium, the influences of the structure of underfloor space on the heat transfer and flow characteristics of the system are simulated, analyzed and compared.The results show that the underfloor space with rational partition is good for improving the heat transfer and flow characteristics of system, and maintaining the cable system in the underfloor space.

Heat Transfer Model and Analysis of Oil-Immersed Electrical Transformers with Heat Pipe Radiator

2012 ◽  
Vol 516-517 ◽  
pp. 312-315
Author(s):  
Guang Hua Li ◽  
Hong Lei Liu ◽  
De Jian Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Heat Pipe ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Cooling Device ◽  
Transformer Design ◽  
Electrical Transformers ◽  
Good Agreement

This paper has formulated a heat transfer model for analyzing the cooling properties of a heat pipe cooling device of oil-immersed electrical transformer. Based on the model, the oil temperature field of a 30 KVA oil-immersed transformer has been numerical simulated, and experiments also had been conducted. Results showed that the numerical simulation has good agreement with experiment results. Results also showed that heat pipe radiator is feasible for oil-immersed electrical transformer cooling. The model can be used to analyze the oil temperature distribution properties in an oil-immersed electrical transformer with heat pipe cooling device, and provide theoretical guide for transformer design and improvement.

Numerical Simulation on Process of Flow and Heat Transfer in Upright Magnesium Reducing Furnace

2011 ◽  
Vol 383-390 ◽  
pp. 6657-6662 ◽  
Author(s):  
Jun Xiao Feng ◽  
Qi Bo Cheng ◽  
Si Jing Yu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Flue Gas ◽  
Gas Flow ◽  
Three Dimensional ◽  
Reaction Heat ◽  
Flow And Heat Transfer ◽  
Major Factors ◽  
High Chemical Reaction

Based on the analysis of structural characteristic superiority, the process of combustion, flue gas flow and heat transfer in the upright magnesium reducing furnace, the three dimensional mathematical model is devoloped. And numerical simulation is performed further with the commercial software FLUENT. Finally, the flow and temperature field in furnace and temperature field in reducing pot have been obtained. The results indicate that the upright magnesium reducing furnace has perfect flue gas flow field and temperature field to meet the challenge of the magnesium reducing process; the major factors that affect the magnesium reducing reaction are the low thermal conductivity of slag and the high chemical reaction heat absorption.

A Comprehensive Heat Transfer Study Inside a Steam Turbine Valve: Experiment, Numerical Simulation and Simplified Model

2021 ◽  
Author(s):  
Xu Zhang ◽  
Hongyi Shao ◽  
Wenwu Zhou ◽  
Wei Zhe Wang ◽  
YingZheng Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Steam Turbine ◽  
Transfer Process ◽  
Electric Heating ◽  
Heating System ◽  
Heat Transfer Process ◽  
Thermal Design ◽  
Simplified Model ◽  
Operational Flexibility

Abstract In a steam turbine system, one of the main factors limiting the operational flexibility is the thermal stress associated with a high temperature gradient within the control valves, which often leads to structural damage during frequent start-up and shut-down cycles. One possible solution is to utilize an electric heating system with appropriate insulation to decrease the warm-up time. Here, an experiment and a numerical simulation were performed using a scaled turbine valve equipped with an electric heating system to understand the heat transfer process. The experiment was conducted at Shanghai Jiao Tong University and had a duration of 100 hours, including three heating-cooling cycles and two heat preservation states. The simulation, which used the commercial software Ansys Fluent 2019 R1 with the finite volume method, was performed to model the experimental heat transfer process. The simulated results showed less than 10% deviation from the measured temperatures. To further improve the computing efficiency, a simplified model based on the lumped parameter method was proposed and validated. This model can predict the valve temperature in less than 1 minute and showed good agreement for all of the studied cases. The ability of the simplified model to simulate the valve heating-cooling cycles at a high efficiency could accelerate the thermal design process to improve the operational flexibility of steam turbines in the future.

Numerical Simulation of Hot Rolled Coil Temperature Field in Hot Coil Box

2011 ◽  
Vol 338 ◽  
pp. 572-575
Author(s):  
Gui Jie Zhang ◽  
Kang Li ◽  
Ying Zi Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Coil Temperature ◽  
Hot Rolled ◽  
Strip Coil ◽  
Good Agreement

The heat transfer model was developed and the heat transfer of the strip coil stay in the hot coil box was analyzed. The temperature distribution of the strip coil was investigated use the model. The measured results are in good agreement with the calculated ones, has a guiding significance to further improve the technology.

An Analysis of the Heating in Passive Solar Room With Greenhouse

2008 ◽  
Author(s):  
Wei Chen ◽  
Feng Jia Gao
Keyword(s):  
Numerical Simulation ◽  
Gas Flow ◽  
Heat Storage ◽  
Heating System ◽  
Solar Heating ◽  
Solar Absorber ◽  
Passive Solar ◽  
System Properties ◽  
Unsteady Numerical Simulation ◽  
And Storage

In this paper, heating and heat storage in passive solar heating room with greenhouse has been studied. The unsteady numerical simulation is employed to analyze the performance of the flow and temperature field for the typical sunny day of Wuhan, China, in winter in the heating system. The heat storage layer of passive solar heating room has a great effect on temperature distribution and gas flow in heat storage layer of this system. Properties of the bed worked as solar absorber and storage layer have also been studied.

Research on Temperature Field Distribution of Heavy Hydrostatic Thrust Bearing Rotation-Workbench at Different Rotating Velocity

2011 ◽  
Vol 239-242 ◽  
pp. 2703-2706
Author(s):  
Jun Peng Shao ◽  
Xiao Dong Yang ◽  
Yun Fei Wang ◽  
Xiao Qiu Xu ◽  
Yan Qin Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Field Distribution ◽  
Thrust Bearing ◽  
State Equation ◽  
Temperature Field Distribution ◽  
Hydrostatic Bearing ◽  
Average Temperature ◽  
Heat Transfer Theory

Based on heat transfer theory, thermodynamics steady state equation of hydrostatic bearing, thermal mathematical model of hydrostatic bearing and boundary condition of numerical simulation is established. Temperature field distribution of hydrostatic bearing at different velocity is numerical simulated. Regularity of the influence of velocity on temperature field of heavy hydrostatic thrust bearing is revealed. The results show that, velocity impacted a significant influence on heat transfer and temperature field distribution of hydrostatic bearing. Average temperature of workbench steadily declined as velocity increasing, while average temperature of base gradually increased; both of them emerged serious heat concentration, but the cooling situation of workbench is better than base. The numerical simulation results could provide theoretical basis for temperature control scheme design which will improve the stability and reliability during hydrostatic bearing operation.

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