scholarly journals Exergetic efficiency analysis of hydrogen–air detonation in pulse detonation combustor using computational fluid dynamics

2016 ◽  
Vol 9 (1) ◽  
pp. 44-54 ◽  
Author(s):  
Pinku Debnath ◽  
KM Pandey
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mass Fraction ◽  
Transport Model ◽  
Combustion Process ◽  
Vital Role ◽  
Exergetic Efficiency ◽  
Ansys Fluent ◽  
Pulse Detonation ◽  
Detonation Combustion

Exergy losses during the combustion process, heat transfer, and fuel utilization play a vital role in the analysis of the exergetic efficiency of combustion process. Detonation is thermodynamically more efficient than deflagration mode of combustion. Detonation combustion technology inside the pulse detonation engine using hydrogen as a fuel is energetic propulsion system for next generation. In this study, the main objective of this work is to quantify the exergetic efficiency of hydrogen–air combustion for deflagration and detonation combustion process. Further detonation parameters are calculated using 0.25, 0.35, and 0.55 of [Formula: see text] mass concentrations in the combustion process. The simulations have been performed for converging the solution using commercial computational fluid dynamics package Ansys Fluent solver. The details of combustion physics in chemical reacting flows of hydrogen–air mixture in two control volumes were simulated using species transport model with eddy dissipation turbulence chemistry interaction. From these simulations it was observed that exergy loss in the deflagration combustion process is higher in comparison to the detonation combustion process. The major observation was that pilot fuel economy for the two combustion processes and augmentation of exergetic efficiencies are better in the detonation combustion process. The maximum exergetic efficiency of 55.12%, 53.19%, and 23.43% from deflagration combustion process and from detonation combustion process, 67.55%, 57.49%, and 24.89%, are obtained from aforesaid [Formula: see text] mass fraction. It was also found that for lesser fuel mass fraction higher exergetic efficiency was observed.

Performance Investigation on Single Phase Pulse Detonation Engine Using Computational Fluid Dynamics

2013 ◽  
Author(s):  
Pinku Debnath ◽  
K. M. Pandey
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Combustion Process ◽  
Supersonic Combustion ◽  
Pulse Detonation Engine ◽  
Pulse Detonation ◽  
Detonation Tube ◽  
Wide Range ◽  
Detonation Engine ◽  
Specific Thrust

Pulse detonation engines (PDEs) are new concept propulsion technologies and unsteady propulsion system that operates cyclically and typically consists of four stages, filling of fuel/air mixture, combustion, blow down and purging. Out of these four processes, combustion is the most crucial one since it produces reliable and repeatable detonation wave. Detonation is a supersonic combustion process which is essentially a shock front driven by the energy release from the reaction zone in the flow right behind it. It is based on supersonic mode of combustion and causes rapid burning of a fuel-air mixture, typically tens of thousands of times faster than in a flame, that utilize repetitive detonations to produce thrust or power. PDE offers the potential to provide increased performance while simultaneously reducing engine weight, cost, and complexity relative to conventional propulsion systems currently in service. It has the potential to drastically reduce the cost of orbit transfer vehicle system as well as space vehicle attitude control system and can be used for wide range of military, civil and commercial applications. Due to its obvious advantages, worldwide attention has been paid to the scientific and technical issues concerning PDE. The present study deals with the convergence and divergence nozzle effects on specific thrust and pressure of Pulse Detonation Engine (PDE) using computational fluid dynamics (CFD). Pulse Detonation Engine having 88.3cm length and 9.5cm diameter combustion chamber, convergence nozzle, detonation tube and divergence nozzle were design in Gambit 2.3.16. FLUENT 6.3 predict the flow physics of pressure and specific thrust (Fs), increase in divergence nozzle compared to convergence nozzle and specific thrust of detonation tube was changed with the change of flight Mach number. A three dimension computational unstructured grid was developed which gives the best meshing accuracy as well as computational results. RNG k-ε turbulence model was used for the mass flow rate, pressure and velocity contours analysis with standard wall function.

The Study of Waste-to-Energy Plant Combustion Characteristics Based on Computational Fluid Dynamics

2013 ◽  
Vol 871 ◽  
pp. 259-262
Author(s):  
Gui Chuan Hu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mass Fraction ◽  
Combustion Process ◽  
Waste To Energy ◽  
Pollutant Emissions ◽  
Plant Design ◽  
Detailed Understanding ◽  
Energy Plant ◽  
Proximate And Ultimate Analyses

The combustion process for using municipal solid waste as a fuel within a waste to energy plant calls for a detailed understanding of the following phenomena. Firstly, this process depends on many input parameters such as proximate and ultimate analyses, the season of the year, primary and secondary inlet air velocities and, secondly, on output parameters such as the temperatures or mass fraction of the combustible products. The variability and mutual dependence of these parameters can be difficult to manage in practice. Another problem is how these parameters can be tuned to achieving optimal combustible conditions with minimal pollutant emissions, during the plant-design phase. In order to meet these goals, a waste-to-energy plant with bed combustion was investigated by using computational fluid-dynamics approach.

scholarly journals Computational Fluid Dynamics-Based Efficiency Evaluation of Ammonia Containing Gas Combustion in the Claus Reaction Furnaces

2021 ◽  
Vol 134 (3) ◽  
pp. 29-34
Author(s):  
I. R. Karimov ◽  
◽  
А. V. Klinov ◽  
L. R. Minibaeva ◽  
◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Acid Gases ◽  
Ansys Fluent ◽  
Gas Combustion ◽  
Actual Performance ◽  
Recovery Unit ◽  
Sulphur Recovery

Based on the computational fluid dynamics method using ANSYS Fluent software, we carried out a simulation of acid gases combustion process in the Claus furnaces with further combustion of ammonia containing gas originated from sour water stripper. The sulphur recovery unit of the heavy residue conversion complex owned by TAIF-NK was considered as a research subject. As per the results of CFD-simulation, the optional scenarios were defined for utilization of ammonia containing acid gases in the sulphur recovery unit by adjustment of gas composition, thermodynamic conditions, as well as by controlling the flow pattern in the Furnace. The data obtained agree quite well with the actual performance parameters of the existing unit and the findings in the public domain.

Transportation Performance of Highly Concentrated Coal-Water Slurries Prepared from Indian Coals

2014 ◽  
Vol 592-594 ◽  
pp. 869-873 ◽  
Author(s):  
Arunanshu Chakravarthy ◽  
Satish Kumar ◽  
S.K. Mohapatra
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Rheological Behaviour ◽  
Pseudoplastic Fluid ◽  
Ansys Fluent ◽  
Water Slurry ◽  
Solids Concentration ◽  
Coal Water Slurry ◽  
Indian Coals ◽  
Fluid Behaviour

The rheological behaviour of concentrated coal-water slurries prepared from three different Indian coals were investigated using an Anton Paar rheometer. The perspective was laid in to study the effect of solids concentration on the rheological behaviour of coal water slurry. It was observed that coal water slurry exhibited non-Newtonian pseudoplastic fluid behaviour at concentrations above 30 % by weight. The apparent viscosity varied with the amount of coal in the slurry. The rheological data were utilized to predict the pressure drop characteristics of coal water slurry flowing through a 53 mm diameter slurry pipeline using ANSYS Fluent 14.0 computational fluid dynamics code.

Reactive computational fluid dynamics modelling methane–hydrogen admixtures in internal combustion engines part II: Large eddy simulation

2020 ◽  
pp. 146808742091034
Author(s):  
Jann Koch ◽  
Christian Schürch ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Large Eddy Simulation ◽  
Combustion Process ◽  
Flame Speed ◽  
Hydrogen Addition ◽  
Eddy Simulation ◽  
Modelling Framework ◽  
Large Eddy ◽  
Dynamics Modelling

Fuels based on admixtures of methane/natural gas and hydrogen are a promising way to reduce CO2 emissions of spark ignition engines and increase their efficiency. A lot of work was conducted experimentally, whereas only limited numerical work is available in the context of three-dimensional modelling of the full engine cycle. This work addresses this fact by proposing a reactive computational fluid dynamics modelling framework to consider the effects of hydrogen addition on the combustion process. Part I of this two-part study focuses on the modelling and crucial considerations in order to predict the mean cycle based on the G-equation combustion model using the Reynolds-averaged Navier–Stokes equations. There, the effect of increased burning speed was globally captured by increasing the flame speed coefficient A, appearing in the considered flame speed closure. The proposed simplified modelling of the early flame stage proved to be robust for the conducted hydrogen variation from 0 to 50 vol% H2 for stoichiometric and lean operation. Scope of this work, Part II, are cyclic fluctuations and the hydrogen influence thereon using large eddy simulation and the proposed modelling framework. The model is probed towards its capabilities to predict the fluctuation of the combustion process for 0 and 50 vol% H2 and correlations influencing the observed peak pressure of the individual cycle are presented. It is shown that the considered approach is capable to reproduce the cyclic fluctuations of the combustion process under the influence of hydrogen addition as well as lean operation. The importance of the early flame phase with respect to arising fluctuations is highlighted as well as the contribution of the resolved scales in terms of the flame front wrinkling.

Experimental and simulation study of thermal accumulation in an enclosed vehicle

2019 ◽  
Vol 233 (14) ◽  
pp. 3621-3629
Author(s):  
Sing Ngie David Chua ◽  
Boon Kean Chan ◽  
Soh Fong Lim
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
Heat Accumulation ◽  
Ansys Fluent ◽  
Direct Exposure ◽  
Car Park

Thermal accumulation in a car cabin under direct exposure to sunlight can be extremely critical due to the risk of heatstroke especially to children who are left unattended in the car. There are very limited studies in the literature to understand the thermal behaviour of a car that is parked in an open car park space and the findings are mostly inconsistent among researchers. In this paper, the studies of thermal accumulation in an enclosed vehicle by experimental and computational fluid dynamics simulation approaches were carried out. An effective and economical method to reduce the heat accumulation was proposed. Different test conditions such as fully enclosed, fully enclosed with sunshade on front windshield and different combinations of window gap sizes were experimented and presented. Eight points of measurement were recorded at different locations in the car cabin and the results were used as the boundary conditions for the three-dimensional computational fluid dynamics simulation. The computational fluid dynamics software used was ANSYS FLUENT 16.0. The results showed that the application of sunshade helped to reduce thermal accumulation at car cabin by 11.5%. The optimum combination of windows gap size was found to be with 4-cm gap on all four windows which contributed to a 21.1% reduction in car cabin temperature. The results obtained from the simulations were comparable and in agreement with the experimental tests.

Review of Computational Fluid Dynamics Studies on Chemical Looping Combustion

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Yali Shao ◽  
Ramesh K. Agarwal ◽  
Xudong Wang ◽  
Baosheng Jin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Oxygen Carrier ◽  
Combustion Process ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Flow Process ◽  
Gas Leakage ◽  
Fuel Reactor ◽  
Energy Penalty

Abstract Chemical looping combustion (CLC) is an attractive technology to achieve inherent CO2 separation with low energy penalty. In CLC, the conventional one-step combustion process is replaced by two successive reactions in two reactors, a fuel reactor (FR) and an air reactor (AR). In addition to experimental techniques, computational fluid dynamics (CFD) is a powerful tool to simulate the flow and reaction characteristics in a CLC system. This review attempts to analyze and summarize the CFD simulations of CLC process. Various numerical approaches for prediction of CLC flow process are first introduced and compared. The simulations of CLC are presented for different types of reactors and fuels, and some key characteristics including flow regimes, combustion process, and gas-solid distributions are described in detail. The full-loop CLC simulations are then presented to reveal the coupling mechanisms of reactors in the whole system such as the gas leakage, solid circulation, redox reactions of the oxygen carrier, fuel conversion, etc. Examples of partial-loop CLC simulation are finally introduced to give a summary of different ways to simplify a CLC system by using appropriate boundary conditions.

Computational Fluid Dynamics Modelling of a Load Sensing Proportional Valve

2019 ◽  
Author(s):  
Alessandro Corvaglia ◽  
Giorgio Altare ◽  
Roberto Finesso ◽  
Massimo Rundo
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Steady State ◽  
Complex Geometry ◽  
Ansys Fluent ◽  
Proportional Valve ◽  
Fluid Forces ◽  
Load Sensing ◽  
Cfd Models ◽  
Dynamics Modelling

Abstract In this paper, two 3D CFD models of a load sensing proportional valve are contrasted. The models were developed with two different software, Simerics PumpLinx® and ANSYS Fluent®. In both cases the mesh was dynamically modified based on the fluid forces acting on the local compensator. In the former, a specific template for valves was used, in the latter a user-defined function was implemented. The models were validated in terms of flow rate and pressure drop for different positions of the main spool by means of specific tests. Two configurations were tested: with the local compensator blocked and free to regulate. The study has brought to evidence the reliability of the CFD models in evaluating the steady-state characteristics of valves with complex geometry.

High Swept-Back Delta Wing Flow

2014 ◽  
Vol 1016 ◽  
pp. 377-382 ◽  
Author(s):  
Thi Kim Dung Hoang ◽  
Phu Khanh Nguyen ◽  
Yoshiaki Nakamura
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Lift Force ◽  
Delta Wing ◽  
Air Velocity ◽  
Rolling Angle ◽  
Ansys Fluent ◽  
Absolute Value ◽  
Numerical Tests ◽  
Low Speed Wind Tunnel

In this study, an experimentally and numerically investigation was carried out to obtain characteristics (lift force, drag force ...) on 74.5 degree Delta wing. The experiment tests were conducted at Hanoi University of Science and Technology low-speed wind tunnel facility, whereas the numerical tests were performed using the commercial computational fluid dynamics software ANSYS/FLUENT. The apparition of the vortices upon the Delta wing caused the negative pressure distribution on the wing which reached a maximum absolute value at the vortex core. The characteristics of high swept-back Delta wing were investigated at air velocity of 10 m/s and attack angle of 20 degree in changing the rolling angle of the wing from 0 to 20 degree.

Sign in / Sign up

Export Citation Format

Share Document