The Thermo-Hydro Coupled Model of Low-Temperature Rock In Consideration of Phase Change

2008 ◽  
Vol 33-37 ◽  
pp. 645-650 ◽  
Author(s):  
Quan Sheng Liu ◽  
Guang Miao Xu ◽  
Yue Xiu Wu
Keyword(s):  
Mathematical Model ◽  
Low Temperature ◽  
Phase Change ◽  
Initial Conditions ◽  
Coupled Model ◽  
Physical And Mechanical Properties ◽  
Element Model ◽  
Coupling Model ◽  
Cold Regions ◽  
Transmission Pipeline

Considering the influence of phase change and temperature variation on the physical and mechanical properties of low-temperature rock in cold regions, the mathematical model for the Thermo-Hydro(TH) coupled problem is proposed based on the theory of convective heat transfer for porous medium. In this model, the influence of moisture migration on heat conduction in rock is taken into account, as well as the influence of temperature gradient on the seepage. The involved parameters are determined according to the related equations given in this paper. Then the finite element model of a gas transmission pipeline in cold region is established using the proposed mathematical model. By selecting suitable boundary conditions, initial conditions and heat computation parameters, the freezing problem of low-temperature rock surrounding the pipeline is analyzed. The calculated values of the temperature field and the measured data are basically consistent, which indicates that the proposed TH coupling model for rock in cold regions is reasonable and reliable.

The Research on the Heat Transfer Process of Low Temperature Hot Water Radiant Heating Phase Change Wallboard

2013 ◽  
Vol 800 ◽  
pp. 18-21
Author(s):  
Quan Ying Yan ◽  
Li Hang Yue ◽  
Ran Huo
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Low Temperature ◽  
Phase Change ◽  
Physical Model ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Hot Water ◽  
Radiant Heating ◽  
Heating Phase

In this paper, physical model and mathematical model of the hot water radiant heating phase change wallboard were built. The heat transfer process of wallboard was simulated to analyze different influencing factors and optimize the design of the hot water heating phase change wallboard. The research results can provide reference and basis to the optimization of low temperature hot water radiant heating phase change wallboard.

Phase Change Material Freezing in an Energy Storage Module for a Micro Environmental Control System

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
H. Ezzat Khalifa ◽  
Mustafa Koz
Keyword(s):  
Mathematical Model ◽  
Phase Change ◽  
Phase Change Material ◽  
Environmental Control ◽  
Finite Thickness ◽  
Element Model ◽  
Storage Device ◽  
Freezing Process ◽  
Latent Heat Storage ◽  
Change Material

Abstract This study analyzes phase change material (PCM) freezing process in a novel latent heat storage device (LHSD). Heat is removed from the PCM with an embedded evaporator. A mathematical model of freezing in a finite-thickness PCM slab is presented. An experimentally validated reduced-order model (ROM) based on the mathematical model was developed to analyze the heat transfer between the freezing PCM and an evaporating refrigerant flowing inside a flat, microchannel tube coil embedded in the PCM. A detailed finite element model (FEM) of the same device was also developed and employed to verify the validity of the ROM over a wider range of conditions. The freezing times and total “cooling” stored in the PCM computed by the ROM agree very well with those computed by the detailed FEM. The ROM executes in ∼1 min for a full heat exchanger, compared with more than 10 h for the FEM, making the former much more practical for use in parametric analysis and optimization of design alternatives.

Deformation Analysis of Aero Thin-Walled Workpiece Under Multi-Stress Coupled Effect

2007 ◽  
Author(s):  
Dong Lu ◽  
Jianfeng Li ◽  
Yiming Rong ◽  
Jie Sun ◽  
Song Zhang ◽  
...  
Keyword(s):  
Initial Stress ◽  
Initial Conditions ◽  
Stable Condition ◽  
Coupled Model ◽  
Element Model ◽  
Milling Process ◽  
Deformation Analysis ◽  
Reaction Forces ◽  
Milling Forces ◽  
The Finite Element Model

Cutting stress coupled with clamping stress and initial stress affects the workpiece deformation. To predicate the workpiece deformation during machining, the multi-stress coupled model was developed. The finite element model of milling process is established and the milling forces were predicted. The predicated milling force, clamping force and initial stress were taken as initial conditions and were inputted into the multi-stress coupled model. Workpiece deformation during machining and reaction forces of locators were predicated. To maintain workpiece in a stable condition during machining, reaction forces of the locators when the cutting tool moving along the clamp side must be monitored.

scholarly journals Low to Middle Vibro-Acoustic Noise Prediction in Ship Cabin by Using Plate-Cavity Coupling Model

2018 ◽  
Vol 25 (s2) ◽  
pp. 149-157
Author(s):  
Zhenwei Zhou ◽  
Jiaming Wu
Keyword(s):  
Finite Element ◽  
Acoustic Noise ◽  
Coupled Model ◽  
Element Model ◽  
Coupling Model ◽  
Structural Vibration ◽  
Modal Expansion ◽  
Cabin Noise ◽  
Cavity Coupling ◽  
The One

Abstract A plate-cavity coupling method based on modal expansion technique in the closed sound cavity was introduced, aiming at ship cabin structural noise. Using this method, a coupled equation was established. The structural vibration acceleration of the target cabin was extracted from a ship vibration response calculation, applied to the model. Then the target cabin noise value was obtained through numerical calculation. The effectiveness and reliability of the method were validated through experiments. The coupled model predicts noise in the cabin does not require fluid finite element model of the cabin air, thus greatly reducing the calculation time compared with the pure finite element method. It was shown that the method is suitable for the calculation of noise in a single ship cabin; the method has a high calculation efficiency. Furthermore, the calculated result is a continuum. On the one hand, it can be conveniently converted to an octave or 1/3 octave according to the specification. On the other hand, the form of the continuum also provides a corresponding response to the subsequent vibration and noise control.

The effect of pressure on the compressibility of aluminum alloys

2020 ◽  
pp. 102-107
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Liquid Metal ◽  
Control Systems ◽  
Physical And Mechanical Properties ◽  
Reliable Data ◽  
Output Process ◽  
Automated Control ◽  
Input And Output ◽  
Crystallization Under Pressure

To obtain reliable data on the properties of liquid metal and create automated control systems, the technological process of molding with crystallization under pressure is studied. A mathematical model of the input and output process parameters is developed. It is established that the compressibility of the melt can represent the main controlled parameter influencing on the physical-mechanical properties of the final products. The obtained castings using this technology are not inferior in their physical and mechanical properties to those produced by forging or stamping.

Dynamic Response of the Spectral Element Model by Using the FFT

2007 ◽  
Vol 345-346 ◽  
pp. 845-848
Author(s):  
Joo Yong Cho ◽  
Han Suk Go ◽  
Usik Lee
Keyword(s):  
Fourier Transforms ◽  
Initial Conditions ◽  
Element Model ◽  
Spectral Element ◽  
Dynamic Responses ◽  
Analysis Method ◽  
Euler Beam ◽  
Exact Analytical Solutions ◽  
Simply Supported ◽  
Spectral Analysis Method

In this paper, a fast Fourier transforms (FFT)-based spectral analysis method (SAM) is proposed for the dynamic analysis of spectral element models subjected to the non-zero initial conditions. To evaluate the proposed SAM, the spectral element model for the simply supported Bernoulli-Euler beam is considered as an example problem. The accuracy of the proposed SAM is evaluated by comparing the dynamic responses obtained by SAM with the exact analytical solutions.

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