Electric Heating Biogas Digester Experimental Research and Numerical Simulation of Fluent

2013 ◽  
Vol 724-725 ◽  
pp. 236-240
Author(s):  
Ling Jia ◽  
Shi Lu Xing ◽  
Rui Tian ◽  
Li Ying Wang ◽  
Song Li
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Balance ◽  
Simulation Analysis ◽  
Electric Heating ◽  
Accurate Method ◽  
Dynamic Boundary Conditions ◽  
Experimental Conditions ◽  
Simulation Process ◽  
Good Agreement

In order to verify the correspondence of numerical simulation and experimental results in the electric heating biogas digester system, an electric heating biogas digester experimentdevice was established, and according to the experimental conditions, software Fluent was used to simulate the process of the heat transfer in the system. Before simulation, analyze theexperimental data through the calculation of heat balance and modify it, then use the modifiedexperimental data, compile UDF to characterize the dynamic boundary conditions, choosestandard turbulence model through the Raleigh number, numerical solving the process. Numericalsimulation results show: simulation process basically reflects the experiment, the simulation dataand experimental data are good agreement, and error within 1%. It is concluded that thenumerical simulation analysis is accurate, method is reliable.

Numerical Simulation of Scouring in Overtopping Dam-break Flow

2021 ◽  
Author(s):  
Can Huang ◽  
Xiaoliang Wang ◽  
Qingquan Liu
Keyword(s):  
Numerical Simulation ◽  
Empirical Relationship ◽  
Dam Break ◽  
Experimental Conditions ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Dam Break Flow ◽  
Scouring Process ◽  
Overtopping Erosion ◽  
Good Agreement

<p>Overtopping dam-break flow has great harm to the earthen embankments due to the hydraulic erosion. Some researchers have carried out relevant model experiments, but it is difficult to achieve the experimental conditions for the actual situation. The common numerical simulation is to express the scouring process through the empirical relationship, which obviously could not reflect the real scouring process. In this paper, a new overtopping erosion model using Smoothed Particle Hydrodynamics (SPH) is proposed. When the shear stress on the sediment SPH particle exceeds the critical stress, the erosion process begins. Then, when a sediment SPH particle is completely eroded, it will begin to move and is described as a non-Newtonian fluid. The un-incipient sediment particles are treated as boundary. This model is well validated with plane dike-breach experiment, and has also achieved a good agreement with erodible bed dam-break experiment.</p>

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 of Synthetic Heat Transfer in Laminar Nanofluid in a Horizontal Pipe

2014 ◽  
Vol 936 ◽  
pp. 409-414
Author(s):  
Mohsen Mirzaei ◽  
Mostafa Jafari Gishin ◽  
Mohammad Abbaspour
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Convective Heat Transfer Coefficient ◽  
Three Dimensional ◽  
Oxide Nanoparticles ◽  
Aluminum Oxide Nanoparticles ◽  
Horizontal Pipe ◽  
Water Based ◽  
Solid Liquid ◽  
Good Agreement

In this study, the effect of solid-liquid volumetric ratio in laminar flow of nanofluid has been investigated numerically. The conservation equations are utilized in three dimensional elliptical forms for laminar and steady flow, and the effects of adding aluminum oxide nanoparticles to water based-fluid are studied. First, the influence of solid-liquid volumetric ratio on the secondary flow vortices, non-dimensional temperature is investigated for a flow with a fixed low Reynolds number and different Grashof numbers in a horizontal pipe. Then, the effect of variation in solid-liquid volumetric ratio on Nusselt number and convective heat transfer coefficient along the pipe is studied. The results of this study are in good agreement with the current literatures.

scholarly journals Numerical Simulation Analysis of Cavitation Performance of Tandem Propeller

2018 ◽  
Vol 36 (3) ◽  
pp. 509-515 ◽  
Author(s):  
Xiaoxu Du ◽  
Zhengdong Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Cavitation Number ◽  
Hydrodynamic Characteristics ◽  
Turbulent Model ◽  
Cavitation Model ◽  
Cavitation Phenomenon ◽  
Cavitation Performance ◽  
Simulation Results ◽  
Good Agreement

The steady non cavitation hydrodynamic characteristics of CLB4-55-1 tandem propeller and the steady cavitation flows of NACA66 hydrofoil are numerically studied firstly based on the RANS equations of homogeneous multiphase using CFD theory, combined with the SST k-ω turbulent model and Z-G-B cavitation model. Numerical simulation results are in good agreement with the experimental results, which indicates that the numerical method is reliable and accurate. Then, the cavitation performance of the tandem propeller are numerical simulated and analyzed. The results show that the computational model can predict the cavitation performance of tandem propeller accurately. The cavitation performance of tandem propeller is nearly the same as single propeller, however, the cavitation phenomenon of back propeller is greater than the head propeller at certain advance coefficient and cavitation number. The cavitation phenomenon will disappear with the increase of the advance coefficient or the cavitation number.

Effect of Inclined Angle of Radiator on Natural Convective Heat Dissipation Performance

2019 ◽  
Author(s):  
Tengfei Ma ◽  
Wen Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Coefficient ◽  
Natural Convection ◽  
Heat Dissipation ◽  
Deflection Angle ◽  
Experimental Conditions ◽  
Pin Fin ◽  
Inclined Angle ◽  
Gravity Direction

Abstract The effects of inclined angle on the heat transfer of radiators under natural convection are analyzed with experiment and numerical simulation, there are three radiators with straight fin, oblique fin and pin fin respectively (based on 150 × 150 × 45mm). The numerical simulation could agree with the experiment. The straight fin radiator could provide the best heat dissipation performance under experimental conditions and normal installation angle. The pin fin radiator has the largest heat transfer coefficient, around 7 W/m2·K. The influence of deflection angle is discussed on the heat dissipation capability of the radiator. The heat dissipation of the pin fin radiator is less sensitive to the gravity direction than the straight fin and oblique fin ones.

scholarly journals Spatiotemporal Rule of Heat Transfer on a Soil/Finned Tube Interface

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1159 ◽  
Author(s):  
Yongsheng Huang ◽  
Wenbin Li ◽  
Daochun Xu ◽  
Yafeng Wu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Soil Moisture ◽  
Geothermal Energy ◽  
Simulation Analysis ◽  
Finned Tube ◽  
Empirical Formulas ◽  
Simulated Analysis ◽  
The City ◽  
Good Agreement

To efficiently harvest environmental micro-energy from shallow soil, simulated analysis, theoretical arithmetic and experimental verification are performed to explore the spatiotemporal rules of heat transfer on a soil/finned tube interface. Simulations are carried out for 36 types of different working conditions, and the empirical formulas for temperature and heat flux are obtained. The temperature and heat flux can be calculated using the formulas if the soil temperature, soil moisture content and finned tube initial temperature are known. The simulations also show that the highest heat flux can reach approximately 0.30 mW/mm2, and approximately 1507.96 mW of energy can be harvested through the finned tube. Theoretical arithmetic indicates that the heat transfer rate of the copper finned tube is 76.77% higher than that of the bare tube, the highest rate obtained in any study to date. Results also show that the finned tube should be placed where the soil moisture is greater than 30% to get more heat from the soil. A field experiment is carried out in the city of Harbin in Northeast China, where a thermoelectric power generation device has been installed and temperature data have been monitored for a certain time. The results are in good agreement with those obtained from the simulation analysis. The heat transfer processes and heat transfer steady state on the soil/finned tube interface are revealed in this work and are of great importance for the use of geothermal energy.

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.

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