Numerical Simulation and Optimization of a Carbon Monoxide Boiler

2016 ◽  
Author(s):  
Guangwu Tang ◽  
Bin Wu ◽  
Chenn Q. Zhou
Keyword(s):  
Heat Transfer ◽  
Carbon Monoxide ◽  
Flue Gas ◽  
Thermal Efficiency ◽  
Gas Flow ◽  
Combustion Process ◽  
Three Dimensional ◽  
Measurement Data ◽  
Flow Characteristics ◽  
Simulation And Optimization

Carbon monoxide (CO) boilers play an important role in the petroleum refining industry, completing the combustion of CO in the flue gas generated by the regeneration of fluidized cracking catalyst. The heat released by the CO combustion is used to generate steam for use in the refinery. The flue gas flow path can have a significant effect on the thermal efficiency and operation safety of the boiler. In this paper, a CO boiler which had been experiencing low thermal efficiency and high operation risks was studied. A three-dimensional (3D) computational fluid dynamics (CFD) model was developed with detailed description on the combustion process, flow characteristics and heat transfer. The results obtained from the model have good agreement with the plant measurement data. The heat transfer between the tubes and the combustion flue gas was optimized by adding a checker wall.

Numerical Simulation on Process of Flow and Heat Transfer in Upright Magnesium Reducing Furnace

2011 ◽  
Vol 383-390 ◽  
pp. 6657-6662 ◽  
Author(s):  
Jun Xiao Feng ◽  
Qi Bo Cheng ◽  
Si Jing Yu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Flue Gas ◽  
Gas Flow ◽  
Three Dimensional ◽  
Reaction Heat ◽  
Flow And Heat Transfer ◽  
Major Factors ◽  
High Chemical Reaction

Based on the analysis of structural characteristic superiority, the process of combustion, flue gas flow and heat transfer in the upright magnesium reducing furnace, the three dimensional mathematical model is devoloped. And numerical simulation is performed further with the commercial software FLUENT. Finally, the flow and temperature field in furnace and temperature field in reducing pot have been obtained. The results indicate that the upright magnesium reducing furnace has perfect flue gas flow field and temperature field to meet the challenge of the magnesium reducing process; the major factors that affect the magnesium reducing reaction are the low thermal conductivity of slag and the high chemical reaction heat absorption.

The Simulation and Optimization on Flow Field in Intake Port of Engine Based on RE and CFD

2014 ◽  
Vol 1079-1080 ◽  
pp. 926-929
Author(s):  
Dan Han ◽  
Qian Wang ◽  
Bing Huan Li ◽  
Guo Jun Zhang ◽  
Shuo Wang
Keyword(s):  
Flow Field ◽  
Laser Scanning ◽  
Gas Flow ◽  
Gasoline Engine ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Intake Port ◽  
Three Dimensional Model ◽  
Simulation And Optimization

Intake port is an important part of the gasoline engine, its structure will influence the gas flow characteristics which directly affects the performance of the engine [1]. In this paper, three-dimensional CFD calculation and structural optimization were used to research the performance of gasoline engine. Firstly, the method of laser scanning and UG software were used to reverse modeling engine exhaust port and get the three-dimensional model. Secondly, after setting boundary conditions and turbulence models, the air flowing through the intake ports were simulated by FLUENT software respectively. Finally, based on numerical methods, the pressure field, velocity field were shown. The results of the simulation of flow field characteristics analysis show that the simulation and experimental results are in good agreement.

Investigation of Operational Effects on Slab Heating Characteristics in a Pusher-Type Reheat Furnace With Continuous Slab Motion

2017 ◽  
Author(s):  
Xiang Liu ◽  
Guangwu Tang ◽  
Armin Silaen ◽  
Jeffrey Cox ◽  
Kurt Johnson ◽  
...  
Keyword(s):  
Combustion Process ◽  
Three Dimensional ◽  
Measurement Data ◽  
Flow Characteristics ◽  
Milling Process ◽  
Heating Process ◽  
Transient Heating ◽  
Ansys Fluent ◽  
Reheat Furnace ◽  
Continuous Slab

Reheat furnace is an important component in hot milling process consuming large amount of fuel and energy. In order to investigate the operational effects on slab temperature distribution, a three-dimensional computational fluid dynamics (CFD) model was developed to simulate the flow characteristics, combustion process, and multi-scale heat transfer inside a reheating furnace with continuous slab motion. ANSYS Fluent®, which is a mature commercial package, was used to conduct numerical simulation. The operation process was modeled with specific slab line-ups and fuel input conditions. The slab motion was modeled with dynamic mesh based on a transient heating process. The model was validated with measurement data at the ArcelorMittal hot rolling mill. The model aims to predict the temperature field in the furnace and the temperature evolution of the slab as it travels through the furnace.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

Analysis of a Virtual Prototype First-Stage Rotor Blade Using Integrated Computer-Based Design Tools

2006 ◽  
Author(s):  
Michel Arnal ◽  
Christian Precht ◽  
Thomas Sprunk ◽  
Tobias Danninger ◽  
John Stokes
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Thermal Loading ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Life Assessment ◽  
Element Analysis ◽  
Pressure Losses ◽  
Cooling Channels ◽  
Internally Cooled

The present paper outlines a practical methodology for improved virtual prototyping, using as an example, the recently re-engineered, internally-cooled 1st stage blade of a 40 MW industrial gas turbine. Using the full 3-D CAD model of the blade, a CFD simulation that includes the hot gas flow around the blade, conjugate heat transfer from the fluid to the solid at the blade surface, heat conduction through the solid, and the coolant flow in the plenum is performed. The pressure losses through and heat transfer to the cooling channels inside the airfoil are captured with a 1-D code and the 1-D results are linked to the three-dimensional CFD analysis. The resultant three-dimensional temperature distribution through the blade provides the required thermal loading for the subsequent structural finite element analysis. The results of this analysis include the thermo-mechanical stress distribution, which is the basis for blade life assessment.

Extended Thermodynamic Approach for Non-Equilibrium Gas Flow

2013 ◽  
Vol 13 (5) ◽  
pp. 1330-1356 ◽  
Author(s):  
G. H. Tang ◽  
G. X. Zhai ◽  
W. Q. Tao ◽  
X. J. Gu ◽  
D. R. Emerson
Keyword(s):  
Heat Transfer ◽  
Equilibrium State ◽  
Gas Flow ◽  
Rarefied Gas ◽  
Flow Characteristics ◽  
Bimodal Distribution ◽  
Thermodynamic Approach ◽  
Navier Stokes ◽  
Extended Thermodynamic ◽  
Non Equilibrium

AbstractGases in microfluidic structures or devices are often in a non-equilibrium state. The conventional thermodynamic models for fluids and heat transfer break down and the Navier-Stokes-Fourier equations are no longer accurate or valid. In this paper, the extended thermodynamic approach is employed to study the rarefied gas flow in microstructures, including the heat transfer between a parallel channel andpressure-driven Poiseuille flows through a parallel microchannel andcircular microtube. The gas flow characteristics are studied and it is shown that the heat transfer in the non-equilibrium state no longer obeys the Fourier gradient transport law. In addition, the bimodal distribution of streamwise and spanwise velocity and temperature through a long circular microtube is captured for the first time.

Optimized Chaotic Heat Exchanger Configurations for Process Industry: A Numerical Study

2013 ◽  
Author(s):  
Akram Ghanem ◽  
Thierry Lemenand ◽  
Dominique Della Valle ◽  
Hassan Peerhossaini
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Study ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Process Intensification ◽  
Point Of View ◽  
Square Duct ◽  
Square Channel ◽  
Duct Geometry

A numerical investigation of chaotic laminar flow and heat transfer in isothermal-wall square-channel configurations is presented. The computations, based on a finite-volume method with the SIMPLEC algorithm, are conducted in terms of Péclet numbers ranging from 7 to 7×105. The geometries, based on the split-and-recombine (SAR) principle, are first proposed for micromixing purposes, and are then optimized and scaled up to three-dimensional minichannels with 3-mm sides that are capable of handling industrial fluid manipulation processes. The aim is to assess the feasibility of this mass- and heat-transfer technique for out-of-laboratory commercial applications and to compare different configurations from a process intensification point of view. The effects of the geometry on heat transfer and flow characteristics are examined. Results show that the flux recombination phenomenon mimicking the baker’s transform in the SAR-1 and SAR-2 configurations produces chaotic structures and promotes mass transfer. This phenomenon also accounts for higher convective heat transfer exemplified by increased values of the Nusselt number compared to the chaotic continuous-flow configuration and the baseline plain square-duct geometry. Energy expenditures are explored and the overall heat transfer enhancement factor for equal pumping power is calculated. The SAR-2 configuration reveals superior heat-transfer characteristics, enhancing the global gain by up to 17-fold over the plain duct heat exchanger.

Gas Flow and Heat Transfer Analysis for an Anode Duct in Reduced Temperature SOFCs

2003 ◽  
Author(s):  
Jinliang Yuan ◽  
Masoud Rokni ◽  
Bengt Sunde´n
Keyword(s):  
Heat Transfer ◽  
Fuel Cell ◽  
Porous Layer ◽  
Gas Flow ◽  
Porous Electrode ◽  
Three Dimensional ◽  
Gas Permeation ◽  
Heat Transfer Analysis ◽  
Fuel Cell Performance ◽  
Flow And Heat Transfer

In this study, a fully three-dimensional calculation method has been further developed to simulate and analyze various processes in a thick anode duct. The composite duct consists of a porous layer, the flow duct and solid current connector. The analysis takes the electrochemical reactions into account. Momentum and heat transport together with gas species equations have been solved by coupled source terms and variable thermo-physical properties (such as density, viscosity, specific heat, etc.) of the fuel gases mixture. The unique fuel cell conditions such as the combined thermal boundary conditions on solid walls, mass transfer (generation and consumption) associated with the electrochemical reaction and gas permeation to / from the porous electrode are applied in the analysis. Results from this study are presented for various governing parameters in order to identify the important factors on the fuel cell performance. It is found that gas species convection has a significant contribution to the gas species transport from / to the active reaction site; consequently characteristics of both gas flow and heat transfer vary widely due to big permeation to the porous layer in the entrance region and species mass concentration related diffusion after a certain distance downstream the inlet.

Flow Characteristics in a Three-Dimensional Rectangular Channel With a Pair of Ribs Placed Symmetrically at the Channel Walls

2000 ◽  
Author(s):  
M. Singh ◽  
P. K. Panigrahi ◽  
G. Biswas
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Complex Flow ◽  
Energy Equations

Abstract A numerical study of rib augmented cooling of turbine blades is reported in this paper. The time-dependent velocity field around a pair of symmetrically placed ribs on the walls of a three-dimensional rectangular channel was studied by use of a modified version of Marker-And-Cell algorithm to solve the unsteady incompressible Navier-Stokes and energy equations. The flow structures are presented with the help of instantaneous velocity vector and vorticity fields, FFT and time averaged and rms values of components of velocity. The spanwise averaged Nusselt number is found to increase at the locations of reattachment. The numerical results are compared with available numerical and experimental results. The presence of ribs leads to complex flow fields with regions of flow separation before and after the ribs. Each interruption in the flow field due to the surface mounted rib enables the velocity distribution to be more homogeneous and a new boundary layer starts developing downstream of the rib. The heat transfer is primarily enhanced due to the decrease in the thermal resistance owing to the thinner boundary layers on the interrupted surfaces. Another reason for heat transfer enhancement can be attributed to the mixing induced by large-scale structures present downstream of the separation point.

INFLUENCE OF FLUE GAS PATTERN FLOW IN BOILER RADIANT SECTION ON HEAT TRANSFER

2021 ◽  
pp. 1-16
Author(s):  
Branislav Jacimovic ◽  
Srbislav Genic ◽  
Nikola Jacimovic
Keyword(s):  
Heat Transfer ◽  
Flue Gas ◽  
Gas Flow ◽  
Plug Flow ◽  
Integral Model ◽  
Engineering Practice ◽  
Conductive Heat ◽  
Small Deviations ◽  
Proposed Model ◽  
Perfect Mixing

Abstract During the sizing of the radiant zone in boilers and furnaces, the most often used method is the Lobo-Evans model. This method is based on the perfect mixing model for flue gas flow inside the fire box, which represents a conservative or pessimistic flow pattern. This paper presents a different, optimistic model which is based on the plug flow for flue gas flow which results in the largest possible heat duty. The proposed model is given in two distinct forms – integral and numerical. As shown in the paper, the integral model results in small deviations with respect to the numerical model and, as such, is well suited for the engineering practice. Paper also presents an engineering approach to the calculation of the conductive heat transfer through the membrane wall, which is shown to be sufficiently accurate and simple for engineering calculations.

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