scholarly journals Understanding the unsteady pressure field inside combustion chambers of compression-ignited engines using a computational fluid dynamics approach

2018 ◽  
Vol 21 (8) ◽  
pp. 1273-1285 ◽  
Author(s):  
Antonio J Torregrosa ◽  
Alberto Broatch ◽  
Xandra Margot ◽  
Josep Gomez-Soriano
Keyword(s):  
Combustion Chamber ◽  
Pressure Field ◽  
Independent Solution ◽  
Combustion Noise ◽  
Spray Angle ◽  
Combustion Chambers ◽  
Unsteady Pressure ◽  
Compression Ignition Engines ◽  
Performance And Emissions ◽  
System Configurations

In this article, a numerical methodology for assessing combustion noise in compression ignition engines is described with the specific purpose of analysing the unsteady pressure field inside the combustion chamber. The numerical results show consistent agreement with experimental measurements in both the time and frequency domains. Nonetheless, an exhaustive analysis of the calculation convergence is needed to guarantee an independent solution. These results contribute to the understanding of in-cylinder unsteady processes, especially of those related to combustion chamber resonances, and their effects on the radiated noise levels. The method was applied to different combustion system configurations by modifying the spray angle of the injector, evidencing that controlling the ignition location through this design parameter, it is possible to decrease the combustion noise by minimizing the resonance contribution. Important efficiency losses were, however, observed due to the injector/bowl matching worsening which compromises the performance and emissions levels.

Fast-Burn Combustion Chamber Design for Natural Gas Engines

1998 ◽  
Vol 120 (1) ◽  
pp. 232-236 ◽  
Author(s):  
R. L. Evans ◽  
J. Blaszczyk
Keyword(s):  
Combustion Chamber ◽  
Engine Performance ◽  
Fuel Mixture ◽  
Performance Parameters ◽  
Combustion Chambers ◽  
Natural Gas Engines ◽  
Chamber Design ◽  
Performance And Emissions ◽  
Unburned Hydrocarbons ◽  
Fuel Mixtures

The work presented in this paper compares the performance and emissions of the UBC “Squish-Jet” fast-burn combustion chamber with a baseline bowl-in-piston (BIP) chamber. It was found that the increased turbulence generated in the fastburn combustion chambers resulted in 5 to 10 percent faster burning of the air–fuel mixture compared to a conventional BIP chamber. The faster burning was particularly noticeable when operating with lean air–fuel mixtures. The study was conducted at a 1.7 mm clearance height and 10.2:1 compression ratio. Measurements were made over a range of air–fuel ratios from stoichiometric to the lean limit. At each operating point all engine performance parameters, and emissions of nitrogen oxides, unburned hydrocarbons, and carbon monoxide were recorded. At selected operating points a record of cylinder pressure was obtained and analyzed off-line to determine mass-burn rate in the combustion chamber. Two piston designs were tested at wide-open throttle conditions and 2000 rpm to determine the influence of piston geometry on the performance and emissions parameters. The UBC squish-jet combustion chamber design demonstrates significantly better performance parameters and lower emission levels than the conventional BIP design. Mass-burn fraction calculations showed a significant reduction in the time to burn the first 10 percent of the charge, which takes approximately half of the time to burn from 10 to 90 percent of the charge.

Effect of Re-Entrant and Toroidal Combustion Chambers in a DICI Engine

2015 ◽  
Vol 787 ◽  
pp. 722-726 ◽  
Author(s):  
Sozhi Arumugam ◽  
Pitchandi Kasivisvanathan ◽  
M. Arventh ◽  
P. Maheshkumar
Keyword(s):  
Carbon Monoxide ◽  
Combustion Chamber ◽  
Peak Pressure ◽  
Direct Injection ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Combustion Chambers ◽  
Brake Thermal Efficiency ◽  
Performance And Emissions ◽  
Toroidal Chamber

This paper presents the experimental work to investigate the effect of Re-entrant and Toroidal combustion chambers in a DICI Engine. The two combustion chambers namely Re-entrant combustion chamber (RCC) and Toroidal combustion chamber (TCC) were fitted in a 4.4 kW single cylinder Direct Injection Compression Ignition (DICI) engine and tests were conducted with diesel. The influences of the combustion chamber geometry characteristics on combustion, performance and emissions characteristics have been investigated. This investigation shows the peak pressure of re-entrant chamber is higher than that of toroidal chamber. The heat release rate and brake thermal efficiency for re-entrant chamber are slightly higher than that of toroidal chamber. Specific fuel consumption is lower for toroidal chamber than that of re-entrant chamber. The enhancement in reduction of carbon monoxide, hydrocarbon is observed for Re-entrant chamber compared to the Toroidal chamber. Oxides of nitrogen are reduced for toroidal chamber than that of re-entrant chamber.

Analysis of Pressure Oscillations Data in Gas Turbine Annular Combustion Chamber Equipped With Passive Damper

2005 ◽  
Author(s):  
M. Mastrovito ◽  
S. M. Camporeale ◽  
A. Forte ◽  
B. Fortunato
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Pressure Field ◽  
Stability Limit ◽  
Outlet Temperature ◽  
Test Bed ◽  
Combustion Chambers ◽  
Pressure Oscillations ◽  
Theoretical Approaches ◽  
The Stability

Growing environmental awareness, the current legislations, and the increasing competition in the energy market lead gas turbine manufacturers to develop combustion chambers that have to guarantee low NOx emissions, low pressure drop and high combustor outlet temperature. Modern annular and can-type gas turbine combustion chambers, able to work in lean premixed mode, show a remarkable attitude to produce flame instabilities, well known as humming. Many theoretical approaches have been proposed in order to describe the phenomenon and predict the stability margin of the burner. Experimental tests are needed to assess mathematical models and to evaluate the effects of either active or passive methodologies adopted to reduce combustion driven instabilities. Tests have been carried out at the Ansaldo Caldaie test bed on a real-size annular combustion chamber, equipped with a certain number of Helmholtz resonators. The combustion chamber has been instrumented with piezoelectric and opto-electronic transducers in order to determine the pressure field both in proximity of the instability limit and in humming condition. When pressure data are collected before than humming appears, pressure oscillations are much lower than those gathered in humming conditions; therefore, by using sensors designed to work under the pressure levels characterising the humming conditions, difficulties arise in proximity of the stability limit due the low signal-to-noise ratio. In this paper some techniques used to analyse the data gathered from the tests will be shown. Moreover, a simple algorithm capable to analyse a large amount of data and to synthesise them into a few significant parameters useful for the spectral analysis of the pressure field, has been validated by means of both real and simulated signals.

scholarly journals Modeling of Spray Combustion with a Steady Laminar Flamelet Model in an Aeroengine Combustion Chamber Based on OpenFOAM

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Yinli Xiao ◽  
Zupeng Wang ◽  
Zhengxin Lai ◽  
Wenyan Song
Keyword(s):  
Combustion Chamber ◽  
High Performance ◽  
Numerical Models ◽  
Spray Combustion ◽  
Combustion Chambers ◽  
Flamelet Model ◽  
Steady Laminar ◽  
Good Agreement ◽  
Laminar Flamelet ◽  
Laminar Flamelet Model

The development of high-performance aeroengine combustion chambers strongly depends on the accuracy and reliability of efficient numerical models. In the present work, a reacting solver with a steady laminar flamelet model and spray model has been developed in OpenFOAM and the solver details are presented. The solver is firstly validated by Sandia/ETH-Zurich flames. Furthermore, it is used to simulate nonpremixed kerosene/air spray combustion in an aeroengine combustion chamber with the RANS method. A comparison with available experimental data shows good agreement and validates the capability of the new developed solver in OpenFOAM.

A General Rezoning Technique for KIVA3V Internal Combustion Engines CFD Simulations

2010 ◽  
Author(s):  
Randy P. Hessel ◽  
Ettore Musu ◽  
Salvador M. Aceves ◽  
Daniel L. Flowers
Keyword(s):  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Ad Hoc ◽  
National Laboratory ◽  
Internal Combustion ◽  
Computational Time ◽  
Combustion Engines ◽  
Combustion Chambers ◽  
Time Step ◽  
Engine Cycle

A computational mesh is required when performing CFD-combustion modeling of internal combustion engines. For combustion chambers with moving pistons and valves, like those in typical cars and trucks, the combustion chamber shape changes continually in response to piston and valve motion. The combustion chamber mesh must then also change at each time step to reflect that change in geometry. The method of changing the mesh from one computational time step to the next is called rezoning. This paper introduces a new method of mesh rezoning for the KIVA3V CFD-combustion program. The standard KIVA3V code from Los Alamos National Laboratory comes with standard rezoners that very nicely handle mesh motion for combustion chambers whose mesh does not include valves and for those with flat heads employing vertical valves. For pent-roof and wedge-roof designs KIVA3V offers three rezoners to choose from, the choice depending on how similar a combustion chamber is to the sample combustion chambers that come with KIVA3V. Often, the rezoners must be modified for meshes of new combustion chamber geometries to allow the mesh to successfully capture change in geometry during the full engine cycle without errors. There is no formal way to approach these modifications; typically this requires a long trial and error process to get a mesh to work for a full engine cycle. The benefit of the new rezoner is that it replaces the three existing rezoners for canted valve configurations with a single rezoner and has much greater stability, so the need for ad hoc modifications of the rezoner is greatly reduced. This paper explains how the new rezoner works and gives examples of its use.

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