A Coupled Numerical Study of Slab Temperature and Gas Temperature in the Walking-Beam-Type Slab Reheating Furnace

2008 ◽  
Vol 54 (6) ◽  
pp. 625-646 ◽  
Author(s):  
Mei-Jiau Huang ◽  
Chia-Tsung Hsieh ◽  
Shih-Tuen Lee ◽  
Chao-Hua Wang
Keyword(s):  
Numerical Study ◽  
Gas Temperature ◽  
Reheating Furnace ◽  
Slab Temperature ◽  
Beam Type

2-D Transient Radiative Heat Transfer Analysis on the Slab in a Walking-Beam-Type Reheating Furnace

2014 ◽  
Vol 610 ◽  
pp. 993-997 ◽  
Author(s):  
Jun Bo Huang ◽  
Jiin Yuh Jang ◽  
Chien Nan Lin ◽  
Chao Hua Wang
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Thermal Radiation ◽  
Transient Heat Conduction ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Gas Temperature ◽  
Reheating Furnace ◽  
Hot Gas ◽  
Beam Type

A two-dimensional mathematical heat transfer model for the prediction of temperature distribution within the slab has been developed by considering the thermal radiation in the walking-beam-type reheating furnace chamber and transient heat conduction in the slab, respectively. The steel slabs are heated up through the preheating, heating, and soaking zones in the furnace. Heat transfer characteristics and temperature uniformity of the slab is investigated by changing hot gas temperature. Comparison with the in-situ experimental data show that the present heat transfer model works well for the prediction of thermal behavior of the slab in the reheating furnace. The skid mark severity decreases with an increase in hot gas temperature. Keywords: Reheating Furnace, Thermal Radiation, Transient heat conduction

scholarly journals Numerical study on characteristics of combustion and pollutant formation in a reheating furnace

2018 ◽  
Vol 22 (5) ◽  
pp. 2103-2112 ◽  
Author(s):  
Fengsheng Qi ◽  
Zisong Wang ◽  
Baokuan Li ◽  
Zhu He ◽  
Jakov Baleta ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Nitrogen Oxides ◽  
Numerical Study ◽  
Fuel Efficiency ◽  
Sensitivity Study ◽  
Combustion Model ◽  
Total Energy Consumption ◽  
Reheating Furnace ◽  
Fuel Flow ◽  
Beam Type

Energy consumption of fuel-fired industrial furnace accounts for about 23% of the national total energy consumption every year in China. Meanwhile, the reduction of combustion-generated pollutants in furnace has become very important due to the stringent environment laws and policy introduced in the recent years. It is therefore a great challenge for the researchers to simultaneously enhance the fuel efficiency of the furnace while controlling the pollution emission. In this study, a transient 3-D mathematical combustion model coupled with heat transfer and pollution formation model of a walking-beam-type reheating furnace has been developed to simulate the essential combustion, and pollution distribution in the furnace. Based on this model, considering nitrogen oxides formation mechanism, sensitivity study has been carried out to investigate the influence of fuel flow rate, air-fuel ratio on the resultant concentration of nitrogen oxides in the flue gas. The results of present study provide valuable information for improving the thermal efficiency and pollutant control of reheating furnace.

scholarly journals A Numerical Study of Skid Marks on the Slabs in a Walking-Beam Type Slab Reheating Furnace

2010 ◽  
Vol 57 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Chia-Tsung Hsieh ◽  
Mei-Jiau Huang ◽  
Shih-Tuen Lee ◽  
Chao-Hua Wang
Keyword(s):  
Numerical Study ◽  
Reheating Furnace ◽  
Beam Type

scholarly journals Numerical Study of Heat Transfer Intensification in a Circular Tube Using a Thin, Radiation-Absorbing Insert. Part 1: Thermo-Hydraulic Characteristics

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4596
Author(s):  
Piotr Bogusław Jasiński
Keyword(s):  
Heat Transfer ◽  
Flow Resistance ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Cylindrical Tube ◽  
Radiation Absorption ◽  
Fluid Temperature ◽  
Gas Temperature ◽  
Insert Size ◽  
Channel Diameter

The presented paper, which is the first of two parts, shows the results of numerical investigations of a heat exchanger channel in the form of a cylindrical tube with a thin insert. The insert, placed concentrically in the pipe, uses the phenomenon of thermal radiation absorption to intensify the heat transfer between the pipe wall and the gas. Eight geometric configurations of the insert size were numerically investigated using CFD software, varying its diameter from 20% to 90% of the pipe diameter and obtaining the thermal-flow characteristics for each case. The tests were conducted for a range of numbers Re = 5000–100,000 and a constant temperature difference between the channel wall and the average gas temperature of ∆T = 100 °C. The results show that the highest increase in the Nu number was observed for the inserts with diameters of 0.3 and 0.4 of the channel diameter, while the highest flow resistance was noted for the inserts with diameters of 0.6–0.7 of the channel diameter. The f/fs(Re) and Nu/Nus(Re) ratios are shown on graphs indicating how much the flow resistance and heat transfer increased compared to the pipe without an insert. Two methods of calculating the Nu number are also presented and analysed. In the first one, the average fluid temperature of the entire pipe volume was used to calculate the Nu number, and in the second, only the average fluid temperature of the annular portion formed by the insert was used. The second one gives much larger Nu/Nus ratio values, reaching up to 8–9 for small Re numbers.

A Numerical Study on the Slab Heating Characteristics in a Reheating Furnace With the Formation and Growth of Scale on the Slab Surface

2009 ◽  
Author(s):  
Dong Eun Lee ◽  
Jung Hyun Jang ◽  
Man Young Kim
Keyword(s):  
Heat Transfer ◽  
Present Model ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Radiant Heat ◽  
Transfer Model ◽  
Radiant Heat Transfer ◽  
Reheating Furnace ◽  
Combustion Gases ◽  
Scale Layer

In this work, the development of a mathematical heat transfer model for a walking-beam type reheating furnace is described and preliminary model predictions are presented. The model can predict the heat flux distribution within the furnace and the temperature distribution in the slab throughout the reheating furnace process by considering the heat exchange between the slab and its surroundings, including the radiant heat transfer among the slabs, the skids, the hot combustion gases and the furnace wall as well as the gas convection heat transfer in the furnace. In addition, present model is designed to be able to predict the formation and growth of the scale layer on the slab in order to investigate its effect on the slab heating. A comparison is made between the predictions of the present model and the data from an in situ measurement in the furnace, and a reasonable agreement is found. The results of the present simulation show that the effect of the scale layer on the slab heating is considerable.

Effect of the burner position on an austenitizing process in a walking-beam type reheating furnace

2019 ◽  
Vol 153 ◽  
pp. 633-645 ◽  
Author(s):  
Alex M. García ◽  
Andrés F. Colorado ◽  
Julián E. Obando ◽  
Carlos E. Arrieta ◽  
Andrés A. Amell
Keyword(s):  
Reheating Furnace ◽  
Beam Type

scholarly journals Experimental and Numerical Study of a Thermal Expansion Gyroscope for Different Gases

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 360 ◽  
Author(s):  
Guillaume Kock ◽  
Philippe Combette ◽  
Marwan Tedjini ◽  
Markus Schneider ◽  
Caroline Gauthier-Blum ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Gas Flow ◽  
Numerical Study ◽  
Rotational Velocity ◽  
Measurement Range ◽  
Gas Temperature ◽  
Hot Air ◽  
Working Principle ◽  
Set Up ◽  
Different Gases

A new single-axis gas thermal gyroscope without proof mass is presented in this paper. The device was designed, manufactured and experimentally characterized. The obtained results were compared to numerical simulation. The working principle of the gyroscope is based on the deflection of a laminar gas flow caused by the Coriolis effect. A bidirectional hot air flow is generated by alternating activation of two suspended resistive micro-heaters. The heated gas is encapsulated in a semi-open cavity and the gas expands primarily inside the cavity. The thermal expansion gyroscope has a simple structure. Indeed, the device is composed of a micromachined cavity on which three bridges are suspended. The central bridge is electrically separated into two segments enabling to set up two heaters which may be supplied independently from each other. The two other bridges, placed symmetrically on each side of the central bridge, are equipped with temperature detectors which measure variations in gas temperature. The differential temperature depends on the rotational velocity applied to the system. Various parameters such as the heating duty cycle, the type of the gas and the power injected into the heaters have been studied to define the optimal working conditions required to obtain the highest level of sensitivity over a measurement range of around 1000°/s. The robustness of the device has also been tested and validated for a shock resistance of 10,000 g for a duration of 400 µs.

The Effect of Hot-Streaks on HP Vane Surface and Endwall Heat Transfer: An Experimental and Numerical Study

2005 ◽  
Vol 129 (1) ◽  
pp. 32-43 ◽  
Author(s):  
T. Povey ◽  
K. S. Chana ◽  
T. V. Jones ◽  
J. Hurrion
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cooling System ◽  
Numerical Study ◽  
Guide Vane ◽  
Inlet Temperature ◽  
Temperature Profiles ◽  
Gas Temperature ◽  
Hot Streak

Pronounced nonuniformities in combustor exit flow temperature (hot-streaks), which arise because of discrete injection of fuel and dilution air jets within the combustor and because of endwall cooling flows, affect both component life and aerodynamics. Because it is very difficult to quantitatively predict the effects of these temperature nonuniformities on the heat transfer rates, designers are forced to budget for hot-streaks in the cooling system design process. Consequently, components are designed for higher working temperatures than the mass-mean gas temperature, and this imposes a significant overall performance penalty. An inadequate cooling budget can lead to reduced component life. An improved understanding of hot-streak migration physics, or robust correlations based on reliable experimental data, would help designers minimize the overhead on cooling flow that is currently a necessity. A number of recent research projects sponsored by a range of industrial gas turbine and aero-engine manufacturers attest to the growing interest in hot-streak physics. This paper presents measurements of surface and endwall heat transfer rate for a high-pressure (HP) nozzle guide vane (NGV) operating as part of a full HP turbine stage in an annular transonic rotating turbine facility. Measurements were conducted with both uniform stage inlet temperature and with two nonuniform temperature profiles. The temperature profiles were nondimensionally similar to profiles measured in an engine. A difference of one-half of an NGV pitch in the circumferential (clocking) position of the hot-streak with respect to the NGV was used to investigate the affect of clocking on the vane surface and endwall heat transfer rate. The vane surface pressure distributions, and the results of a flow-visualization study, which are also given, are used to aid interpretation of the results. The results are compared to two-dimensional predictions conducted using two different boundary layer methods. Experiments were conducted in the Isentropic Light Piston Facility (ILPF) at QinetiQ Farnborough, a short-duration engine-sized turbine facility. Mach number, Reynolds number, and gas-to-wall temperature ratios were correctly modeled. It is believed that the heat transfer measurements presented in this paper are the first of their kind.

scholarly journals Numerical Study of Heat and Mass Transfer during the Evaporative Drying of Porous Media

2020 ◽  
Vol 307 ◽  
pp. 01050
Author(s):  
Karima SELLAMI ◽  
M’barek FEDDAOUI ◽  
Nabila LABSI ◽  
M’hand OUBELLA ◽  
Youb Khaled BENKAHLA
Keyword(s):  
Porous Media ◽  
Layer Thickness ◽  
Porous Layer ◽  
Mass Flow ◽  
Numerical Study ◽  
Vertical Channel ◽  
Drying Rate ◽  
Gas Temperature ◽  
Drying Process ◽  
Simpler Algorithm

The paper deals with numerical study of drying process of porous media of sand during the evaporation of a liquid saturated porous layer within parallel vertical channel. The liquid and air streams are modeled as two coupled laminar boundary layers incorporating non-Darcian models of the inertia and boundary effects. The governing equations and the associated boundary conditions are discretized by means of the finite volume method implemented on a staggered mesh and the velocity-pressure coupling is processed by the SIMPLER algorithm. The influences of the inlet mass flow of the drying gas, porous layer thickness and the porosity on the drying process are analyzed. Results show that the drying rate of the porous media is improved by the reduction of the porosity and porous layer thickness a large drying rate is obtained with high inlet mass flow and high inlet gas temperature.

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