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.

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.

Significant of Isothermal Flow Studies for High Swirling Flow in Unconfined Burner

2015 ◽  
Vol 789-790 ◽  
pp. 477-483
Author(s):  
A.R. Norwazan ◽  
M.N. Mohd Jaafar
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Turbulent Flows ◽  
Recirculation Zone ◽  
Swirling Flow ◽  
Numerical Study ◽  
Tangential Velocity ◽  
Radial Distance ◽  
Navier Stokes ◽  
Reacting Flow

This paper is presents numerical simulation of isothermal swirling turbulent flows in a combustion chamber of an unconfined burner. Isothermal flows of with three different swirl numbers, SN of axial swirler are considered to demonstrate the effect of flow axial velocity and tangential velocity to define the center recirculation zone. The swirler is used in the burner that significantly influences the flow pattern inside the combustion chamber. The inlet velocity, U0 is 30 m/s entering into the burner through the axial swirler that represents a high Reynolds number, Re to evaluate the differences of SN. The significance of center recirculation zone investigation affected by differences Re also has been carried out in order to define a good mixing of air and fuel. A numerical study of non-reacting flow into the burner region is performed using ANSYS Fluent. The Reynolds–Averaged Navier–Stokes (RANS) realizable k-ε turbulence approach method was applied with the eddy dissipation model. An attention is focused in the flow field behind the axial swirler downstream that determined by transverse flow field at different radial distance. The results of axial and tangential velocity were normalized with the U0. The velocity profiles’ behaviour are obviously changes after existing the swirler up to x/D = 0.3 plane. However, their flow patterns are similar for all SN after x/D = 0.3 plane towards the outlet of a burner.

scholarly journals Numerical Study on Response Characteristics of Solid Rocket Pintle Motor

2019 ◽  
Author(s):  
Jeevan Sapkota ◽  
Yi Hua Xu ◽  
Hai Jun Sun
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Total Pressure ◽  
Numerical Study ◽  
Rocket Motor ◽  
Chamber Pressure ◽  
Head Model ◽  
Solid Rocket Motor ◽  
Rapid Changes ◽  
Solid Rocket

Pintle technology is currently a versatile technology used in a solid rocket motor (SRM) to control the desired thrust by changing the nozzle throat area, while effectively controlling the chamber pressure at the same time. The sudden movement of the pintle can induce rapid changes in the flow field and the occurrence of pressure oscillations inside the combustion chamber. The analysis of such rapid changes is essential to design an efficient controllable pintle rocket motor for a better thrust regulation. Two-dimensional axisymmetric models with mesh generation and required boundary condition were designed to analyze the effects of three different pintle head shape models in SRM thrust regulation effect. Dynamic mesh method was used with specific velocity for moving plug/pintle in the numerical analysis of SRM thrust regulation. The effects of different pintle head models on the flow field, combustion chamber pressure, mass-flow rate, thrust and Mach number were investigated. According to the analysis of total pressure response time, the simulation data revealed that circular pintle head model responded faster among three different models. According to the thrust effect, parabolic pintle has the maximum value of thrust and the greatest total pressure recovery coefficient among all pintle head models.

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 Investigation on the Effects of Flame Propagation in Rotary Engine Performance With Leakage and Different Recess Shapes Using Three-Dimensional Computational Fluid Dynamics

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Thirumal Valavan Harikrishnan ◽  
Suryanarayana Challa ◽  
Dachapalli Radhakrishna
Keyword(s):  
Combustion Chamber ◽  
Flame Propagation ◽  
Compression Ratio ◽  
Peak Pressure ◽  
Three Dimensional ◽  
Engine Performance ◽  
Front Propagation ◽  
Fuel Mixture ◽  
Experimental Results ◽  
Rotary Engine

This study was carried out with an objective to develop a 3D simulation methodology for rotary engine combustion study and to investigate the effect of recess shapes on flame travel within the rotating combustion chamber and its effects on engine performance. The relative location of spark plugs with respect to the combustion chamber has significant effect on flame travel, affecting the overall engine performance. The computations were carried out with three different recess shapes using iso-octane (C8H18) fuel, and flame front propagation was studied at different widths from spark location. Initially, a detailed leakage study was carried out and the flow fields were compared with available experimental results. The results for first recess with compression ratio 9.1 showed that the flow and vortex formations were similar to that of actual model. The capability of the 3D model to predict the combustion reaction rate precisely as that of practical engine is presented with comparison to experimental results. This study showed that the flame propagation is dominant toward the leading apex of the rotor chamber, and the air/fuel mixture region in the engine midplane, between the two spark plugs, has very low flame propagation compared to the region in the vicinity of spark. The air/fuel mixture in midplane toward the leading apex burns partially and most of the mixture toward the trailing apex is left unburnt. Recommendations have been made for optimal positioning of the spark plugs along the lateral axis of the engine. In the comparison study with different recess shapes, lesser cavity length corresponding to a higher compression ratio (CR) of 9.6 showed faster flame propagation toward leading side. Also, mass trapped in working chamber reduced and developed higher burn rate and peak pressure resulting in better fuel conversion efficiency. Third recess with lesser CR showed reduced burn rates and lower peak pressure.

Numerical Study of the Combined Free-Forced Convection and Mass Transfer Flow Past a Vertical Porous Plate in a Porous Medium with Heat Generation and Thermal Diffusion

2006 ◽  
Vol 11 (4) ◽  
pp. 331-343 ◽  
Author(s):  
M. S. Alam ◽  
M. M. Rahman ◽  
M. A. Samad
Keyword(s):  
Mass Transfer ◽  
Flow Field ◽  
Differential Equations ◽  
Forced Convection ◽  
Heat Generation ◽  
Numerical Study ◽  
Porous Plate ◽  
Integration Scheme ◽  
Suction Parameter ◽  
Transfer Flow

The problem of combined free-forced convection and mass transfer flow over a vertical porous flat plate, in presence of heat generation and thermaldiffusion, is studied numerically. The non-linear partial differential equations and their boundary conditions, describing the problem under consideration, are transformed into a system of ordinary differential equations by using usual similarity transformations. This system is solved numerically by applying Nachtsheim-Swigert shooting iteration technique together with Runge-Kutta sixth order integration scheme. The effects of suction parameter, heat generation parameter and Soret number are examined on the flow field of a hydrogen-air mixture as a non-chemical reacting fluid pair. The analysis of the obtained results showed that the flow field is significantly influenced by these parameters.

Effect of Chemical Hythane Composition on Pressure in Combustion Chamber of Engine

2019 ◽  
pp. 36-42
Author(s):  
A. P. Shaikin ◽  
I. R. Galiev
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Power Plants ◽  
Engine Speed ◽  
Combustion Engine ◽  
Fuel Mixture ◽  
Maximum Pressure ◽  
Chamber Volume ◽  
Excess Air ◽  
Scientific Papers

The article analyzes the influence of chemical composition of hythane (a mixture of natural gas with hydrogen) on pressure in an engine combustion chamber. A review of the literature has showed the relevance of using hythane in transport energy industry, and also revealed a number of scientific papers devoted to studying the effect of hythane on environmental and traction-dynamic characteristics of the engine. We have studied a single-cylinder spark-ignited internal combustion engine. In the experiments, the varying factors are: engine speed (600 and 900 min-1), excess air ratio and hydrogen concentration in natural gas which are 29, 47 and 58% (volume).The article shows that at idling engine speed maximum pressure in combustion chamber depends on excess air ratio and proportion hydrogen in the air-fuel mixture – the poorer air-fuel mixture and greater addition of hydrogen is, the more intense pressure increases. The positive effect of hydrogen on pressure is explained by the fact that addition of hydrogen contributes to increase in heat of combustion fuel and rate propagation of the flame. As a result, during combustion, more heat is released, and the fuel itself burns in a smaller volume. Thus, the addition of hydrogen can ensure stable combustion of a lean air-fuel mixture without loss of engine power. Moreover, the article shows that, despite the change in engine speed, addition of hydrogen, excess air ratio, type of fuel (natural gas and gasoline), there is a power-law dependence of the maximum pressure in engine cylinder on combustion chamber volume. Processing and analysis of the results of the foreign and domestic researchers have showed that patterns we discovered are applicable to engines of different designs, operating at different speeds and using different hydrocarbon fuels. The results research presented allow us to reduce the time and material costs when creating new power plants using hythane and meeting modern requirements for power, economy and toxicity.

scholarly journals Experimental and Numerical Study of Proton Exchange Membrane Fuel Cells with a Novel Compound Flow Field

ACS Omega ◽  
2021 ◽  
Vol 6 (34) ◽  
pp. 21892-21899
Author(s):  
Yixiang Wang ◽  
Lei Wang ◽  
Xianhang Ji ◽  
Yulu Zhou ◽  
Mingge Wu
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Proton Exchange Membrane ◽  
Numerical Study ◽  
Proton Exchange ◽  
Exchange Membrane
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