Three-dimensional finite discrete element-based contact heat transfer model considering thermal cracking in continuous–discontinuous media

A transient heat transfer model is developed for a solar reactor prototype for H2O and CO2 splitting via two-step non-stoichiometric ceria cycling. Counter-rotating cylinders of reactive and inert materials cycling between high and low temperature zones permit continuous operation and heat recovery. To guide the reactor design a transient three-dimensional heat transfer model is developed based on transient energy conservation, accounting for conduction, convection, radiation, and chemical reactions. The model domain includes the rotating cylinders, a solar receiver cavity, and insulated reactor body. Radiative heat transfer is analyzed using a combination of the Monte Carlo method, Rosseland diffusion approximation, and the net radiation method. Quasi-steady state distributions of temperatures, heat fluxes, and the non-stoichiometric coefficient are reported. Ceria cycles between temperatures of 1708 K and 1376 K. A heat recovery effectiveness of 28% and solar-to-fuel efficiency of 5.2% are predicted for an unoptimized reactor design.

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Fast three-dimensional heat transfer model for computing internal temperatures in the bearing housing of automotive turbochargers

International Journal of Engine Research ◽

10.1177/1468087418804949 ◽

2018 ◽

Vol 21 (8) ◽

pp. 1286-1297 ◽

Cited By ~ 4

Author(s):

Antonio Gil ◽

Andrés Omar Tiseira ◽

Luis Miguel García-Cuevas ◽

Tatiana Rodríguez Usaquén ◽

Guillaume Mijotte

Keyword(s):

Heat Transfer ◽

Coke Formation ◽

Three Dimensional ◽

Heat Transfer Model ◽

Operating Conditions ◽

Thermal Design ◽

Working Fluid ◽

Transfer Model ◽

Lumped Model ◽

Bearing System

Each of the elements that make up the turbocharger has been gradually improved. In order to ensure that the system does not experience any mechanical failures or loss of efficiency, it is important to study which engine-operating conditions could produce the highest failing rate. Common failing conditions in turbochargers are mostly achieved due to oil contamination and high temperatures in the bearing system. Thermal management becomes increasingly important for the required engine performance. Therefore, it has become necessary to have accurate temperature and heat transfer models. Most thermal design and analysis codes need data for validation; often the data available fall outside the range of conditions the engine experiences in reality leading to the need to interpolate and extrapolate disproportionately. This article presents a fast three-dimensional heat transfer model for computing internal temperatures in the central housing for non-water cooled turbochargers and its direct validation with experimental data at different engine-operating conditions of speed and load. The presented model allows a detailed study of the temperature rise of the central housing, lubrication channels, and maximum level of temperature at different points of the bearing system of an automotive turbocharger. It will let to evaluate thermal damage done to the system itself and influences on the working fluid temperatures, which leads to oil coke formation that can affect the performance of the engine. Thermal heat transfer properties obtained from this model can be used to feed and improve a radial lumped model of heat transfer that predicts only local internal temperatures. Model validation is illustrated, and finally, the main results are discussed.

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Coupling of a radiative heat transfer model and a three-dimensional combustion model for a circulating fluidized bed furnace

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2014.11.008 ◽

2015 ◽

Vol 76 ◽

pp. 344-356 ◽

Cited By ~ 26

Author(s):

Mohammad Hadi Bordbar ◽

Kari Myöhänen ◽

Timo Hyppänen

Keyword(s):

Heat Transfer ◽

Fluidized Bed ◽

Radiative Heat Transfer ◽

Radiative Heat ◽

Circulating Fluidized Bed ◽

Three Dimensional ◽

Heat Transfer Model ◽

Combustion Model ◽

Transfer Model

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Heat Transfer Model in a Rotary Drum During the Fermentation Process

Journal of Advanced Research in Fluid Mechanics and Thermal Sciences ◽

10.37934/arfmts.77.1.151160 ◽

2020 ◽

Vol 77 (1) ◽

pp. 151-160

Author(s):

Norazaliza Mohd Jamil ◽

Aainaa Izyan Nafsun ◽

Abdul Rahman Mohd Kasim

Keyword(s):

Heat Transfer ◽

Mathematical Model ◽

Heat Transfer Coefficient ◽

Fermentation Process ◽

Transfer Model ◽

Kutta Method ◽

Contact Heat ◽

Contact Heat Transfer ◽

Runge Kutta Method ◽

Rotary Drum

A new mathematical model describing heat transfer during the fermentation process in a rotary drum is proposed. The model includes representations of the kinetic reactions, the temperature of the solid bed, and physical structures within the rotary drum. The model is developed using five ordinary differential equations and was then solved using the Runge-Kutta method embedded in MATLAB software. A reasonable behaviour for the temperature profile to the fermentation process is achieved. The results show that the mass of the solid bed, contact heat transfer coefficient, and the wall temperature has a significant effect on the fermentation process in a rotary drum.

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