scholarly journals Heat transfer analysis of the forced air quenching with non-isothermal and non-uniform oxidation

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253240
Author(s):  
Yue Zhang ◽  
Jian Yang ◽  
Ming-Xin Gao ◽  
Hua Sono
Keyword(s):  
Heat Transfer ◽  
Oxide Scale ◽  
Oxide Layer ◽  
Heat Transfer Analysis ◽  
Heat Transfer Characteristics ◽  
Temperature Oxidation ◽  
Transfer Characteristics ◽  
Quenching Process ◽  
Interfacial Temperature ◽  
Forced Air

In this paper, the heat transfer characteristics of the forced air quenching with non-isothermal and non-uniform oxidation are investigated. By introducing the variations of interfacial temperature and oxygen partial pressure, a three-layered non-isothermal high-temperature oxidation kinetic model is developed, in which a discrete-time modeling method is employed to solve the problem of integration of the transient terms, and a special interfacial grid treatment is used for considering the growth of each oxide layer and updating of the thermal properties. Moreover, a parameter identification method using the multi-objective genetic algorithm is proposed for the inverse solution of the oxidation parabolic parameters based on the measured scale thicknesses in oxidation experiment. A case study of the forced air quenching of a Q235 disk is presented to validate the availability of the developed formulas. Then the interfacial heat transfer characteristics are analyzed, while the numerical solutions with and without oxidation are both performed for in-depth comparison. Results indicate that the active quenching region is mainly centralized in the vicinity of stagnation region. The radial variation regularity of the temperature difference across the total oxide layer is mainly determined by the thermal conductivity and the scale thickness. The existence of the oxide scale actually produces a certain thermal resistance during the quenching process and the effects of the oxide scale increases with the radial coordinate due to the interfacial temperature distribution. The results obtained can provide theoretical derivation for precise control of the internal phase transformation during the forced air quenching process.

Experimental investigation on heat transfer characteristics of oxide layer of molten pool

2021 ◽  
Vol 151 ◽  
pp. 107941
Author(s):  
Zongyang Li ◽  
Huajian Chang ◽  
Kun Han ◽  
Lian Chen ◽  
Fangfang Fang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Oxide Layer ◽  
Molten Pool ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Computational Investigation of Flow and Heat Transfer Characteristics of Impingement Cooling Channel

2013 ◽  
Author(s):  
B. V. N. Ramakumar ◽  
D. S. Joshi ◽  
Murari Sridhar ◽  
Jong S. Liu ◽  
Daniel C. Crites
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Heat Transfer Analysis ◽  
Computational Investigation ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Impingement Cooling ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
High Heat Transfer

Impingement cooling offers very high heat transfer coefficients. Flow field, involved in impingement cooling is dominated by stagnation zone, transition zone and developing zone. Understanding of complex flow phenomenon and its effects on heat transfer characteristics is useful for efficient designing of impingement channels. Computational fluid dynamics (CFD) has emerged as a powerful tool for the analysis of flow and heat transfer systems. Honeywell has been investigating the use of CFD to determine the characteristics of various complex turbine blade cooling heat transfer augmentation methods such as impingement. The objective of this study is to develop CFD methodology which is suitable for computational investigation of flow and heat transfer analysis of impingement cooling through validation. Single row of circular jets impinging on concave (curved) surface has been considered for this study. The validation was accomplished with the test results of Bunker and Metzger [10] and with the correlations of Chupp et al. [7]. The parameters which are varied in this study include jet Reynolds number (Re2B = 6750–10200), target plate distance to jet diameter ratio (Z/d = 3 and 4), and target surface sharpness (i.e. radius ratio, r* = 0.2, 0.4 and 1) the simulations are performed under steady state conditions. Predicted results are compared for local endwall heat transfer results along the curve length of the mid span target wall. Flow field results obtained at different locations are presented to understand the heat transfer behavior.

Analysis of Radiation-Convection Coupled Effects on the Turbine Vane With Different Gas Compositions

2020 ◽  
Author(s):  
Peng Sun ◽  
Xueying Li ◽  
Jing Ren ◽  
Hongde Jiang
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Combustion Products ◽  
Heat Transfer Analysis ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Heat Transfer Characteristics ◽  
Cfd Simulations ◽  
Transfer Characteristics ◽  
Development Direction

Abstract To reduce the emission of greenhouse gases, especially carbon dioxide, the combustion of hydrogen and oxy-fuel is a development direction for the gas turbine systems. Because the fuels are different from the traditional gas turbine which uses natural gas as fuel, the compositions of the working fluid are different, which can lead to differences in heat transfer characteristics. Furth more, in order to get higher overall efficacy, the turbine inlet temperature is becoming higher and higher. The radiation becomes an important factor then must be considered seriously. To study the influence of different gas compositions on heat transfer characteristics, three gas compositions, representing the combustion products of IGCC system, hydrogen turbine system, and the oxy-fuel turbine system, respectively, is chosen in this paper. Based on a real turbine first stage vane, the influence of radiation and gas compositions are both researched using CFD simulations. The results show that different gas compositions can lead to different heat transfer characteristics on the vane. The radiation effect can be dealt with as an independent factor in the turbine heat transfer analysis.

Convective Heat Transfer of Laminar Swirling Pipe Flow with Viscous Dissipation Effects

2021 ◽  
Author(s):  
Andre Damiani Rocha ◽  
Antonio Garrido Gallego
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Viscous Dissipation ◽  
Swirling Flow ◽  
Oil Industry ◽  
High Viscosity ◽  
Heat Transfer Analysis ◽  
Temperature Profiles ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Abstract The oil-water-gas separation is a critical aspect of the treatment of production flows in the oil industry. The segregation of gas bubbles and/or water droplets dispersed in viscous oil by an in-line swirling flow separator has been considered by the oil industry for topside and subsea applications. For high viscosity oils, heat transfer processes can be affected. Works addressing these applications are rare in the literature. In this way, the article presents a numerical investigation on heat transfer characteristics in a decaying swirling flow, considering the effects of viscosity dissipation due to the high viscosity of the fluid. The flow has both velocity and temperature profiles developing simultaneously in a tube with a constant diameter having a uniform wall heat flux in a laminar flow regime, particularly the behavior of heat transfer characteristics for strongly swirling numbers considering viscous dissipation. Three swirl numbers (S = 0.0, 0.3 and 0.7) and five Brinkman numbers (Br = 0.0, 0.1, 0.5, 1.0 and 10.0) were investigated and the effects of those parameters on the dimensionless temperature profiles, Nusselt number and viscous dissipation function were examined. The heat transfer analysis indicated that the swirling flow affects the fluid's axial and radial temperature distribution. They promoted increased fluid in wall temperature and bulk temperature and affected the local Nusselt number distribution.

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