Computational Fluid Dynamics Modeling of a Self-Recuperative Burner and Development of a Simplified Equivalent Radiative Model

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Haytham Sayah ◽  
Maroun Nemer ◽  
Wassim Nehmé ◽  
Denis Clodic
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Time ◽  
Dynamics Modeling ◽  
Gas Combustion ◽  
Experimental Database ◽  
Transfer Mode ◽  
High Temperature Processes ◽  
Burner Model

The solution for dynamic modeling of reheating furnaces requires a burner model, which is simultaneously accurate and fast. Based on the fact that radiative heat transfer is the most dominant heat transfer mode in high-temperature processes, the present study develops a simplified flame representation model that can be used for dynamic simulation of heat transfer in reheating furnaces. The first part of the paper investigates, experimentally and computationally, gas combustion in an industrial burner. Experiments aim at establishing an experimental database of the burner characteristics. This database is compared with numerical simulations in order to establish a numerical model for the burner. The numerical burner model was solved using a commercial computational fluid dynamics (CFD) software (FLUENT 6.3.26). A selection of results is presented, highlighting the usefulness of CFD as a modeling tool for industrial scale burners. In the second part of the paper, a new approach called the “emissive volume approach” is established. This approach consists of replacing the burner flame by a number of emissive volumes that replicates the radiative effect of the flame. Comparisons with CFD results show a difference smaller than 1% is achieved with the emissive volume approach, while computational time is divided by 40.

An Investigation in the Numerical Approach to Solve the Heat Transfer Phenomenon in Gas Turbine

2021 ◽  
pp. 1-23
Author(s):  
Sourabh Kumar ◽  
Ryoichi S. Amano
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Leading Edge ◽  
Internal Cooling ◽  
Dynamics Modeling ◽  
Turbine Cooling ◽  
Gas Turbine Cooling

Abstract The gas turbine engine's extreme conditions need a robust design to produce efficient energy and reliable operation. Flow and thermal analysis are essential for complex aerodynamic and thermodynamic interaction during turbine performance. There is a need to understand and predict the temperature to make the gas turbine engine efficient. This paper will outline the numerical methods applied for primary cooling methods in gas turbine blades. These include impinging leading-edge cooling, internal cooling in the midsection, and pin fin in the trailing edge. The main objective of this paper is to understand the numerical research done on improving gas turbine cooling. The emphasis will be on understanding the present CFD (Computational fluid dynamics) techniques applied for gas turbine cooling and further development. This paper briefly outlines the new conjugate heat transfer based CFD (computational fluid dynamics) modeling techniques that have evolved over the years due to recent computing power development.

Experimental and computational fluid dynamics modeling of a novel tray humidifier column in humidification dehumidification desalination; evaluation of hydrodynamic and heat transfer characteristics

2020 ◽  
Vol 234 (3) ◽  
pp. 275-284
Author(s):  
Taleb Zarei ◽  
Reza Hamidi Jahromi ◽  
Arash Mohammadi Karachi
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Rectangular Cross Section ◽  
Seawater Temperature ◽  
Operating Conditions ◽  
Dynamics Modeling ◽  
Heat Transfer Characteristics ◽  
Computational Fluid Dynamics Modeling ◽  
Transfer Characteristics

In this article, a novel tray humidifier column for humidification dehumidification desalination was proposed. The performance of the humidifier column has been investigated with experimental and computational fluid dynamics simulations. The hydrodynamics and heat transfer characteristics of this tray humidifier has been studied. A stainless steel sieve tray with a rectangular cross section with a dimension of 20 × 50 cm was used in the experimental study. In computational fluid dynamics modeling, a transient three-dimensional model has been developed based on the volume of fluid framework by using standard k-epsilon model. The effect of air and seawater flow rate and inlet seawater temperature on the exit air temperature has been investigated. The results show that the humidifier effectiveness of the tray humidifier column varies between 0.67 and 0.87 depending on operating conditions. Then, tray column can be used in humidification dehumidification desalination systems with advantages such as compact equipment, low-pressure drop, and handling solids or other sources of fouling.

Exploring the potential of machine learning in reducing the computational time/expense and improving the reliability of engine optimization studies

2018 ◽  
Vol 21 (7) ◽  
pp. 1251-1270 ◽  
Author(s):  
Chaitanya Kavuri ◽  
Sage L Kokjohn
Keyword(s):  
Machine Learning ◽  
Fluid Dynamics ◽  
Genetic Algorithm ◽  
Computational Fluid Dynamics ◽  
Regression Model ◽  
Gaussian Process ◽  
Gaussian Process Regression ◽  
Computational Time ◽  
Dynamics Modeling ◽  
Initial Dataset

Past research has shown that multidimensional computational fluid dynamics modeling in combination with a genetic algorithm method is an effective approach for optimizing internal combustion engine design. However, optimization studies performed with a detailed computational fluid dynamics model are time intensive, which limits the practical application of this approach. This study addresses this issue by using a machine learning approach called Gaussian process regression in combination with computational fluid dynamics modeling to reduce the computational optimization time. An approach was proposed where the Gaussian process regression model could be used instead of the computational fluid dynamics model to predict the outputs of the genetic algorithm optimization. In this approach, for every nth generation of the genetic algorithm, the data from the previous n − 1 generations was used to train the Gaussian process regression model. The approach was tested on an engine optimization study with five input parameters. When the genetic algorithm was run solely with computational fluid dynamics, the optimization took 50 days to complete. In comparison with the computational fluid dynamics and Gaussian process regression approach, the computational time was reduced by 62%, and the optimization was completed in 19 days using the same amount of computational resources. Additional parametric studies were performed to investigate the impact of genetic algorithm + Gaussian process regression parameters. Results showed that either reducing the initial dataset size or relaxing the error criterion resulted in increased Gaussian process regression evaluations within the genetic algorithm. However, relaxing the error criterion was found to impact the model predictions negatively. The initial dataset size was found to have a negligible impact on the final optimum design. Finally, the potential of machine learning in further improving the optimization process was explored by using the Gaussian process regression model to check for the robustness of the designs to operating parameter variations during the optimization. The genetic algorithm was repeated with the modified procedure and it was shown that adding the stability check resulted in a different, more reliable and stable optimum solution.

Computational Fluid Dynamics Modeling Flow Field and Side-Wall Heat Transfer in Rectangular Rib-Roughened Passages

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Gongnan Xie ◽  
Shian Li ◽  
Weihong Zhang ◽  
Bengt Sunden
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Gas Turbine ◽  
Side Wall ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Wall Heat Transfer ◽  
Dynamics Modeling

In order to achieve higher thermal efficiency and power output, the gas turbine inlet temperature of gas turbine engine is continuously increased. However, the increasing temperature may exceed the melting point of the blade material. Rib turbulators are often used in the midsection of internal cooling ducts to augment the heat transfer from blade wall to the coolant. This study uses computational fluid dynamics (CFD) to investigate side-wall heat transfer of a rectangular passage with the leading/trailing walls being roughened by continuous or truncated ribs. The inlet Reynolds number is ranging from 12,000 to 60,000. The detailed three dimensional (3D) fluid flow and heat transfer over the side-wall are presented. The overall performances of ribbed passages are compared. It is suggested that the usage of truncated ribs is a suitable way to augment the side-wall heat transfer and improve the flow structure near the leading edge especially under the critical limitation of pressure drop.

scholarly journals Computational Fluid Dynamics Modeling of Rotating Annular VUV/UV Photoreactor for Water Treatment

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 79
Author(s):  
Minghan Luo ◽  
Wenjie Xu ◽  
Xiaorong Kang ◽  
Keqiang Ding ◽  
Taeseop Jeong
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Water Treatment ◽  
Cfd Modeling ◽  
Flow Mode ◽  
Oh Radicals ◽  
Dynamics Modeling ◽  
Rotational Movement ◽  
Contaminant Degradation ◽  
Wide Range

The ultraviolet photochemical degradation process is widely recognized as a low-cost, environmentally friendly, and sustainable technology for water treatment. This study integrated computational fluid dynamics (CFD) and a photoreactive kinetic model to investigate the effects of flow characteristics on the contaminant degradation performance of a rotating annular photoreactor with a vacuum-UV (VUV)/UV process performed in continuous flow mode. The results demonstrated that the introduced fluid remained in intensive rotational movement inside the reactor for a wide range of inflow rates, and the rotational movement was enhanced with increasing influent speed within the studied velocity range. The CFD modeling results were consistent with the experimental abatement of methylene blue (MB), although the model slightly overestimated MB degradation because it did not fully account for the consumption of OH radicals from byproducts generated in the MB decomposition processes. The OH radical generation and contaminant degradation efficiency of the VUV/UV process showed strong correlation with the mixing level in a photoreactor, which confirmed the promising potential of the developed rotating annular VUV reactor in water treatment.

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