Numerical Study on Transient Heat Transfer in a Regenerative Oxidation Bed during the Preheating Process

2010 ◽  
Vol 156-157 ◽  
pp. 829-833
Author(s):  
Yong Qi Liu ◽  
Jin Hui Han ◽  
Yan Yan You ◽  
Zhen Qiang Gao
Keyword(s):  
Heat Transfer ◽  
Flow Reactor ◽  
Solid Phase ◽  
Numerical Study ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Great Influence ◽  
Transient Heat Transfer ◽  
Coal Mine Methane ◽  
Reverse Flow Reactor

The transient heat transfer characteristics of a regenerative oxidation bed placed in a coal mine methane thermal reverse-flow reactor during preheating process are numerically investigated in this paper. The regenerative oxidation bed is modeled in a three-dimensional, unsteady state and laminar flow system, and is assumed as a semitransparent porous media. The calculating results indicate that increasing the inlet mass flow could shorten the time of preheating, specific heat and porosity have a great influence on the heat storage capacity of the regenerative oxidation bed, and the contribution of the solid phase radiation to heat transfer can not be ignored. All these work can help to understand the heat transfer phenomena and mechanism in a regenerative oxidation bed during the preheating process.

scholarly journals Calculated Study of the Influence of Overheating Aluminum Melt on the Dynamics the Granulation Process

2020 ◽  
pp. 84-93
Author(s):  
Alexander P. Skuratov ◽  
Alexander V. Ivlev ◽  
Artem A. Pianykh
Keyword(s):  
Heat Transfer ◽  
Phase Transition ◽  
Solid Phase ◽  
Numerical Study ◽  
Three Dimensional ◽  
Solidification Process ◽  
Square Root ◽  
Effective Heat Capacity ◽  
Granulation Process ◽  
Aluminum Melt

A three-dimensional mathematical model of the solidification process of a liquid metal is considered, taking into account the mobility of the boundaries at which the phase transition is carried out (Stefan boundary value problem). The algorithm of calculation is improved, allowing due to the use of the Dirac δ-function in determining the effective heat capacity to take into account the nonlinearity of the equation of unsteady thermal conductivity and the heat of the phase transition. A numerical study of heat transfer during solidification of lead-containing aluminum melt droplets in air and water is carried out. The influence of droplet size and melt overheating on the solidification dynamics of granules has been studied. An approximate ratio based on the square root law is proposed, taking into account the amount of overheating of the liquid phase and linking the thickness of the formed solid phase with the duration of the granulation process

Numerical Simulation for Temperature of Ceramic Honeycomb Regenerator

2012 ◽  
Vol 562-564 ◽  
pp. 359-362
Author(s):  
Yan Xia Wang ◽  
Min Dong
Keyword(s):  
Flow Reactor ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Design Calculation ◽  
Outlet Temperature ◽  
Length Direction ◽  
Shock Resistance ◽  
Dimensional Simulation ◽  
Reverse Flow Reactor ◽  
Ceramic Honeycomb

Ceramic honeycomb regenerator as a critical component about the coalmine ventilation air methane thermal oxidation was proposed for a self-developed thermal reverse-flow reactor. A three-dimensional simulation model was established to obtain the distribution of temperature and velocity of gas, and the temperature variation of honeycomb at the length direction. The outlet temperature of gas variation with time was also obtained. The result could provide valuable reference for design calculation of the oxidizer unit and the later study of the thermal shock resistance.

scholarly journals Modeling Thermal Oxidation of Coal Mine Methane in a Non-Catalytic Reverse-Flow Reactor

2014 ◽  
Vol 60 (7-8) ◽  
pp. 495-505 ◽  
Author(s):  
Xiaoni Qi ◽  
Yongqi Liu ◽  
Hongqin Xu ◽  
Zeyan Liu ◽  
Ruixiang Liu
Keyword(s):  
Thermal Oxidation ◽  
Coal Mine ◽  
Flow Reactor ◽  
Reverse Flow ◽  
Coal Mine Methane ◽  
Reverse Flow Reactor

scholarly journals Experimental and numerical study of heat transfer and flow characteristics with different placement of the multi-deck display cabinet in supermarket

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 256-265
Author(s):  
Pei Yuan ◽  
Qinghui Zeng ◽  
Zhenglin Lei ◽  
Yixiao Wu ◽  
Yanli Lu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Numerical Study ◽  
Three Dimensional ◽  
Great Influence ◽  
Flow Characteristics ◽  
Air Curtain ◽  
Face To Face ◽  
Placement Method ◽  
The Face

Abstract This work focuses on the heat transfer and flow characteristics with the different placement of the multi-deck display cabinet and tries to optimize the placement position of refrigerated display cabinet. First, the temperature distribution in a refrigerated display cabinet was experimentally investigated. The result showed that the food temperature in front is 3.6–4.8°C higher than back row of the same layer, and temperature fluctuation of 0.3–0.7°C less than the back row. Then, a three-dimensional numerical model of the display cabinet was established, and the k–ε model is employed to compare and analyze the heat transfer and air curtain characteristics. The results show that the placement methods have great influence on the performance of the display cabinet. The face-to-back placement method can acquire a better food refrigeration performance, and the food temperature of the face-to-back placement method is 0.3–0.5°C lower than that of the face-to-face placement method.

Numerical Study on the Effect of Inner Tube Position on Heat Transfer Process in Self-Recuperative Radiant Tube

2011 ◽  
Vol 228-229 ◽  
pp. 676-680 ◽  
Author(s):  
Ye Tian ◽  
Xun Liang Liu ◽  
Zhi Wen
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Numerical Study ◽  
Flame Temperature ◽  
Three Dimensional ◽  
Mathematic Model ◽  
Heat Transfer Process ◽  
Bulk Temperature ◽  
Radiant Tube ◽  
Peak Value

A three-dimensional mathematic model is developed for a 100kw single-end recuperative radiant tube and the simulation is performed with the CFD software FLUENT. Also it is used to investigate the effect of distance between combustion chamber exit and inner tube on heat transfer process. The results suggest that the peak value of combustion flame temperature drops along with the increasing of distance, which leads to low NOX discharging. Also radiant tube surface bulk temperature decreases, which causes radiant tube heating performance losses.

Numerical Simulation of Gas Flow and Heat Transfer in Cross-Wavy Primary Surface Channel for Microtubine Recuperators

2005 ◽  
Author(s):  
H. X. Liang ◽  
Q. W. Wang ◽  
L. Q. Luo ◽  
Z. P. Feng
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Gas Turbine ◽  
Numerical Study ◽  
High Reliability ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
The Cross

Three-dimensional numerical simulation was conducted to investigate the flow field and heat transfer performance of the Cross-Wavy Primary Surface (CWPS) recuperators for microturbines. Using high-effective compact recuperators to achieve high thermal efficiency is one of the key techniques in the development of microturbine in recent years. Recuperators need to have minimum volume and weight, high reliability and durability. Most important of all, they need to have high thermal-effectiveness and low pressure-losses so that the gas turbine system can achieve high thermal performances. These requirements have attracted some research efforts in designing and implementing low-cost and compact recuperators for gas turbine engines recently. One of the promising techniques to achieve this goal is the so-called primary surface channels with small hydraulic dimensions. In this paper, we conducted a three-dimensional numerical study of flow and heat transfer for the Cross-Wavy Primary Surface (CWPS) channels with two different geometries. In the CWPS configurations the secondary flow is created by means of curved and interrupted surfaces, which may disturb the thermal boundary layers and thus improve the thermal performances of the channels. To facilitate comparison, we chose the identical hydraulic diameters for the above four CWPS channels. Since our experiments on real recuperators showed that the Reynolds number ranges from 150 to 500 under the operating conditions, we implemented all the simulations under laminar flow situations. By analyzing the correlations of Nusselt numbers and friction factors vs. Reynolds numbers of the four CWPS channels, we found that the CWPS channels have superior and comprehensive thermal performance with high compactness, i.e., high heat transfer area to volume ratio, indicating excellent commercialized application in the compact recuperators.

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