Influences of Ignition Timing, Spark Plug and Intake Port Locations on the Combustion Performance of a Simulated Rotary Engine

2016 ◽  
Vol 32 (5) ◽  
pp. 579-591 ◽  
Author(s):  
P.-W. Hwang ◽  
X.-C. Chen ◽  
H.-C. Cheng
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Combustion Efficiency ◽  
Intake Port ◽  
Computational Domain ◽  
Ignition Timing ◽  
Combustion Chambers ◽  
Combustion Performance ◽  
Rotary Engine ◽  
Spark Plug

AbstractThe purpose of this paper is to study the flow field of the combustion chamber in a simulated rotary engine by using a computational approach. A dynamic mesh technique is employed to overcome the moving and shape varying computational domain inside the combustion chambers as the rotor is spinning. The key parameters include spark plug timing, leading side spark plug location and intake port location, which are used to investigate their influences on flow field and combustion performance of a rotary engine. It was discovered, with a dual spark plug configuration, that better flame propagation could be obtained through the change of ignition timing. In addition, to change the leading side spark plug location, it was also found that combustion efficiency is improved by shortening the distance from the top dead center (TDC) center line, which is consistent with available experimental results. This research also discovered that the intake port should be properly located in order to prevent pressure loss in the combustion chamber during the compression stroke.

Numerical Study on Flow Field in a Peripheral Ported Rotary Engine Under the Action of Apex Seal Leakage

2020 ◽  
Author(s):  
Baowei Fan ◽  
Yuanguang Wang ◽  
Jianfeng Pan ◽  
Yaoyuan Zhang ◽  
Yonghao Zeng
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Combustion Chamber ◽  
Numerical Study ◽  
Particle Image Velocimetry Data ◽  
Calculation Model ◽  
Flow Area ◽  
Rotary Engine ◽  
Unidirectional Flow ◽  
Rotary Engines

Abstract Apex seal leakage is one of the main defects restricting the performance improvement of rotary engines. The aim of this study is to study the airflow movement in a peripheral ported rotary engine under the action of apex seal leakage. For this purpose, a 3D dynamic calculation model considering apex seal leakage was firstly established and verified by particle image velocimetry data. Furthermore, based on the established 3D model, the flow field in the combustion chamber under the four apex seal leakage gaps (0.02, 0.04, 0.06 and 0.08 mms) and the three engine revolution speeds (2000, 3500, and 5000 RPMs) was calculated. By comparing with the flow field under the condition without leakage, the influences of the existence of apex seal leakage on the velocity field, the turbulent kinetic energy and the volumetric efficiency in the combustion chamber were investigated. Thereinto, the influences of the existence of apex seal leakage on the velocity field is that at the intake stroke, a vortex formed in the middle of the combustion chamber under the condition without apex seal leakage, was intensified by the apex seal leakage action. At the compression stroke, irrespective of the condition with or without apex seal leakage, all vortexes in the combustion chamber are gradually broken into a unidirectional flow. However, there is an obvious "leakage flow area" at the end of combustion chamber due to the existence of apex seal leakage.

Numerical Behaviour of Primary Air Flow Field of a Swirl Injector Under High Pressure and High Temperature Condition

2021 ◽  
Author(s):  
Rampada Rana ◽  
Muthuveerappan Nagalingam ◽  
Saptarshi Basu
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Flow Field ◽  
Spatial Scales ◽  
Atmospheric Condition ◽  
Fixed Time ◽  
Combustion Efficiency ◽  
Computational Domain ◽  
Time Step ◽  
Swirl Injector

Abstract Injector plays pivotal role to meet better combustion performances requirements in terms of combustion efficiency, flame stability, ignition, lower emissions etc. In a multi-swirler injector, the primary swirler mainly dictates the airflow field inside and some extend outside the injector. Present CFD studies have been attempted to characterize the flow field of a swirl injector consisting of conical nozzle fitted with single radial swirler at its upstream. Studies are performed at high pressure and high temperature resulting to high density (increased by around 9 times compared to atmospheric condition) and its impact on the flow field in terms of location of energetic zones useful for fuel atomization. Since direct effect of increase in density lead to increase in turbulence which is helpful for mixing and atomization, this study is helpful to capture the same. Embedded LES based hybrid model has been used where the computational domain divided into 3 zones which are seamlessly connected by capturing the interface fluid dynamics. In LES zone, both the time and spatial scales have been resolved by suitably refining the grids. Analysis is carried out with CFL no. around 2, fixed time step of 1 micro second. The analysis is reasonably able to capture various unsteadiness (PVC, CTRZ, frequencies etc. useful for the atomization of the liquid fuel) which are not available beforehand.

Combination of 1D Code and CFD for Performance Analysis of a Silo Type Gas Turbine Combustor

2010 ◽  
Author(s):  
N. Rasooli ◽  
S. Besharat Shafiei ◽  
H. Khaledi
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Mass Distribution ◽  
Gas Turbines ◽  
Pressure Loss ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Empirical Correlations ◽  
Combustion Chambers ◽  
Cfd Simulations

Whereas Gas Turbines are the most important producers of Propulsion and Power in the world and with attention to the importance of combustion chamber as one of the three basic components of Gas Turbine, various activities in different levels have been done on this component. Because of the environmental limitations and laws related to the pollutants such as NOx and CO, Lean Premixed Combustion Chambers are specially considered in gas turbine industries. This study is part of a Multi-Layer simulation of the whole gas turbine cycle in MPG Company. In this work, the combination of a general 1D code and CFD is used for deriving appropriate performance curves for a 1D and 0D gas turbine design, off-design and dynamic cycle code. This 1D code is a general code which has been developed for different combustion chambers; annular, can-annular, can type and silo type combustion chambers. The purpose of generating this 1D code is the possibility of fast analysis of combustors in different operating conditions and reaching required outputs. This 1D code is a part of a general simulation 1D code for gas turbine and was used for a silo type combustor performance prediction. This code generates required quantities such as pressure loss, exit temperature, liner temperature and mass distribution through the combustion chamber. Mass distribution and pressure loss are analyzed and determined with an electrical analogy. Results derived from 1D code are validated with empirical data available for different combustors. There is appropriate agreement between these experimental and analytical results. Drag coefficients for liner holes are available from experimental data and for burner are calculated as a curve with CFD simulations. What differs this code from other 1D codes for gas turbine combustors is the advantage of using combustion efficiencies evolved from numerical simulation results in different loads. These efficiencies are determined with CFD simulations and are available as maps and inserted into the gas temperature calculation algorithm of 1D code. In other 1D codes in this field, empirical correlations are used for combustion efficiency determination. Combustion efficiency curves for design and off-design conditions in this study are achieved by 2D and 3D simulation of combustion chamber with application of EBU/Finite Rate model and 8 step reactions of CH4 burning. Diffusion flame in low loads and premixed flame in high loads are considered. Flame stability and Lean Blow Out charts are evolved from CFD simulation and Heat transfer is applied with empirical correlations.

Experimental and Numerical Investigation of Different Flame Types Inside a Laboratory Scale RQL Combustion Chamber

2019 ◽  
Author(s):  
Thomas von Langenthal ◽  
Nikolaos Zarzalis ◽  
Marco Konle
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Thermal Power ◽  
Measurement Techniques ◽  
Flame Structure ◽  
Operating Conditions ◽  
Test Rig ◽  
Combustion Chambers ◽  
Primary Zone ◽  
Secondary Air

Abstract RQL (rich burn, quick quench, lean burn) combustion chambers are common in modern aero engines due to their low NOx emissions and good stability. The rich primary zone leads to lower flame temperatures and in combination with the lack of oxygen, the NOx production is low. The mixing of the secondary air must be quick in order to avoid stoichiometric conditions and at the same time must ensure the oxidation of the soot produced in the fuel rich primary zone to keep soot emissions to a minimum. However, the design of such a combustion chamber is complicated due to the complex interaction between the swirling primary flow and the jets of the secondary airflow. In this paper, we present a new test rig, which was designed to study combustion processes inside RQL combustion chambers at atmospheric conditions. The test rig features liquid kerosene combustion and a realistic quenching zone as well as good access for optical and conventional measurement techniques. For realistic engine like conditions the combustion air is preheated to 600 K and the fuel–air equivalence ratio in the primary combustion zone is set to be between Φ = 1.66 and Φ = 1.25, resulting in an overall thermal power between 80 kW and 110 kW. To get insights into the complex flow field inside the combustion chamber unsteady RANS simulations of both the reacting and the non-reacting case were performed using OpenFOAM. The turbulent flow field was modeled using the k-ω-SST model and the combustion was simulated using the Partially Stirred Reactor model. The experimental investigations showed two stable flame types for the same operating conditions with considerable differences in the visible flame structure and soot radiation. The flow field of both of these flame types were measured using a 1.5 kHz 2D PIV System. The numerical simulations showed good overall agreement with the experimental results but could not represent the change in flame type. In order to understand the underlying effects of the flame change the OH* chemiluminescence was recorded and the two-phase flow near the nozzle exit was investigated. This showed that the change in flame structure might arise due to spray dispersion of the pilot fuel nozzle and the recirculation of the secondary air into the primary zone.

scholarly journals The Relationship between In-Cylinder Flow-Field near Spark Plug Areas, the Spark Behavior, and the Combustion Performance inside an Optical S.I. Engine

2019 ◽  
Vol 9 (8) ◽  
pp. 1545 ◽  
Author(s):  
Atsushi Nishiyama ◽  
Minh Khoi Le ◽  
Takashi Furui ◽  
Yuji Ikeda
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Entire Area ◽  
Combustion Performance ◽  
Simultaneous Imaging ◽  
Spark Plug ◽  
Combustion Duration ◽  
Image Velocimetry ◽  
Flame Development ◽  
Cylinder Flow

The stringent regulations that were placed on gasoline vehicles demand significant improvement of the powertrain unit, not only to become cleaner but also more efficient. Therefore, there is a strong need to understand the complex in-cylinder processes that will have a direct effect on the combustion quality. This study applied multiple high-speed optical imaging to investigate the interaction between the in-cylinder flow, the spark, the flame, and combustion performance. These individual elements have been studied closely in the literature but the combined effect is not well understood. Simultaneous imaging of in-cylinder flow and flame tomography using high-speed Particle Image Velocimetry (PIV), as well as simultaneous high-speed spark imaging, were applied to port-injected optical gasoline imaging. The captured images were processed using in-house MATLAB algorithms and the deduced data shows a trend that higher in-cylinder flow velocity near the spark will increase the stretch distance of the spark and decrease the ignition delay. However, these do not have much effect on the combustion duration, and it is the flow-field in the entire area surrounding the flame development that will influence how fast the combustion and flame growth will occur.

Experimental and Numerical Study on the Formation Mechanism of Flow Field in a Side-Ported Rotary Engine Considering Apex Seal Leakage

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Baowei Fan ◽  
Yaoyuan Zhang ◽  
Jianfeng Pan ◽  
Yuanguang Wang ◽  
Peter Otchere
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Formation Mechanism ◽  
Engine Speed ◽  
Peak Pressure ◽  
Numerical Study ◽  
Volumetric Efficiency ◽  
Central Plane ◽  
Rotary Engine ◽  
Volume Efficiency

Abstract The aim of this research is to investigate the influences of apex seal leakage on the formation mechanism of flow field in a side-ported rotary engine by particle image velocimetry (PIV) and computational fluid dynamics (CFD). In this study, a PIV was used to acquire the two-dimensional (2D) flow field on the rotor housing central plane at an engine speed of 700 rpm. A three-dimensional (3D) dynamic simulation model considering leakage through apex seals was established and verified by the 2D-PIV experiment results. Thereafter, CFD analysis was used to further understand the 3D flow field in combustion chamber under the action of apex seal leakage. The simulation results showed that for the three engine speeds (2000, 3500, and 5000 rpm), in the intake stroke, the vortex generated in the front end of combustion chamber under the condition with no leakage, was strengthened and destroyed by the effects of the small (0.02 mm) and the large (0.08 mm) apex seal leakage gaps, respectively. As the apex seal leakage gap increased, the volume efficiency and the peak pressure decreased continuously. The volume efficiency and the peak pressure caused by any fixed apex seal leakage gap decreased with the increase of the engine speed. Compared with the volumetric efficiency of the condition with no leakage at 2000 and 5000 rpm, the volumetric efficiency of apex seal leakage gap of 0.08 mm decreased only by 24.6% at 5000 rpm, but by 41.2% at 2000 rpm.

RANS Based Iso-Thermal CFD Analysis of the Flow Field Created by a Radial Swirler in a Conical Nozzle

2019 ◽  
Author(s):  
Rampada Rana ◽  
Sonu Kumar ◽  
Nagalingam Muthuveerappan
Keyword(s):  
Flow Field ◽  
Maximum Flow ◽  
Field Studies ◽  
Combustion Efficiency ◽  
Computational Domain ◽  
Conical Nozzle ◽  
Ansys Fluent ◽  
Upstream Direction ◽  
Ignition Characteristics ◽  
The Impact

Abstract Improvement of specific fuel consumption and specific thrust of gas turbine engines have necessitated to have better combustion performances requirements in terms of combustion efficiency, flame stability, better ignition characteristics, lower emissions etc. Injector designs play a very pivotal role to meet the above requirements. In this paper steady state flow field studies have been carried out in a conical nozzle fitted with single swirler which is the fundamental part of a typical injector. The aspects of the flow field both inside and outside the injector have been captured by using RANS based calculations of commercial software Ansys Fluent. The computational domain extends from 500mm in the upstream direction and the exit flow of the nozzle is allowed to meet on to a domain of length more than 2000mm. The downstream domain is so chosen that the impact of the wall on to the evaluation of the flow field is found to be negligible resembling the flow field studies in open atmosphere. Realizable k-ε turbulent model and standard wall function were used with wall y+ extended from 30 onwards. The study shows a distinct feature of maximum flow velocity at the exit of the injector lip apart from the presence of regular re-circulation bubble at the exit of the injector.

Numerical Simulation of DI Diesel Engine’s Combustion Chamber Using Several Turbulence Models During Intake and Compression Strokes

2005 ◽  
Author(s):  
Seyed Ali Jazayeri ◽  
Masoud Mirzaei ◽  
Javad Kheyrollahi ◽  
Abdollah Shadaram
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Engine Performance ◽  
Turbulence Models ◽  
Computational Domain ◽  
Compression Process ◽  
Ic Engine ◽  
Performance And Emission

Atomization of the fuel that is injected to the combustion chamber depends on flow field characteristics during the compression process. Mixture formation, mixture preparation rate and delay period are some of the dominant factors in DI diesel engine performance and emission level. This paper presents a new CFD approach simulation of flow field during intake and compression of a four strokes IC engine. In this model a dynamic mesh is used to simulate the moving boundaries of engine parts, such as piston and valves. Computational domain, which is a precise model of one cylinder, is meshed to 300,000–500,000 cells. In our solution three different two-equation turbulence models are used. The capability of each model is highlighted and the results are compared with relevant works. The focus of these turbulence models and three-dimensional simulation of engine flow are to validate the reliability of flow characteristics. The results accurately demonstrate the three-dimensional characteristics of air motion in the swirl chamber and development of vortices.

Effects of Fuel Type on the Performance of Aero Gas Turbine Combustion Chambers, and the Influence of Design Features

1954 ◽  
Vol 58 (528) ◽  
pp. 813-825
Author(s):  
J. G. Sharp
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Combustion Efficiency ◽  
Combustion Stability ◽  
Fuel Type ◽  
Combustion Chambers ◽  
Exhaust Temperature ◽  
Design Changes ◽  
Fuel Characteristics ◽  
Gas Turbine Combustion

SummaryThe performance of aero gas turbine combustion chambers is discussed under the following headings : Combustion efficiency, combustion stability, ease of ignition, deposits, exhaust temperature variation, and smooth combustion. It is shown that, as assessed by these criteria, combustion chamber performance can be significantly affected by fuel characteristics; also that the effects of fuel type can be greatly modified by equipment design changes. The conclusion is that most of the problems- aggravated by fuel characteristics are better solved by modifications to equipment, if fuel availability and cost are not to be adversely affected.

Analysis of Temperature Distribution Over a Gas Turbine Shaft Exposed to a Swirl Combustor Flue

2010 ◽  
Author(s):  
V. Aghakashi ◽  
M. H. Saidi ◽  
A. Ghafourian ◽  
A. A. Mozafari
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Equivalence Ratio ◽  
Vortex Flow ◽  
Combustion Efficiency ◽  
Swirl Flow ◽  
Axial Position ◽  
Combustion Chambers ◽  
Swirl Combustor ◽  
Turbine Shaft

Gas turbine shaft is generally exposed to high temperature gases and may seriously be affected and overheated due to temperature fluctuations in the combustion chamber. Considering vortex flow in the combustion chamber, it may increase the heat release rate and combustion efficiency and also control location of energy release. However, this may result in excess temperature on the combustor equipments and gas turbine shaft. Vortex flow in the vortex engine which is created by the geometry of combustion chamber and conditions of flow field is a bidirectional swirl flow that maintains the chamber wall cool. In this study a new gas turbine combustion chamber implementing a liner around the shaft and liquid fuel feeding system is designed and fabricated. Influence of parameters such as axial position in the combustor direction and equivalence ratio are studied. Experimental results are compared with the numerical simulation by the existing commercial software. Swirl number i.e. ratio of angular flux of angular momentum to angular flux of linear momentum multiplied by nozzle radius, in this study is assumed to be constant. In order to measure the temperature along the liner, K type thermocouples are used. Results show that the heat transfer to the liner at the inlet of combustion chamber is enough high and at the outlet of combustion chamber is relatively low. The effect of parameters such as equivalence ratio and the mass flow rate of oxidizer on the temperature of the liner is investigated and compared with the numerical solution. This type of combustion chambers can be used in gas turbine engines due to their low weight and short length of combustion chamber.

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