scholarly journals Studies on variable swirl intake system for DI diesel engine using computational fluid dynamics

2008 ◽  
Vol 12 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Rathnaraj Jebamani ◽  
Narendra Kumar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Diesel Engine ◽  
Steady Flow ◽  
High Speed ◽  
Mixing Time ◽  
Operating Conditions ◽  
Swirl Ratio ◽  
Partial Load ◽  
Di Diesel Engine

It is known that a helical port is more effective than a tangential port to attain the required swirl ratio with minimum sacrifice in the volumetric efficiency. The swirl port is designed for lesser swirl ratio to reduce emissions at higher speeds. But this condition increases the air fuel mixing time and particulate smoke emissions at lower speeds. Optimum swirl ratio is necessary according to the engine operating condition for optimum combustion and emission reduction. Hence the engine needs variable swirl to enhance the combustion in the cylinder according to its operating conditions, for example at partial load or low speed condition it requires stronger swirl, while the air quantity is more important than the swirl under very high speed or full load and maximum torque conditions. The swirl and charging quantity can easily trade off and can be controlled by the opening of the valve. Hence in this study the steady flow rig experiment is used to evaluate the swirl of a helical intake port design for different operating conditions. The variable swirl plate set up of the W06DTIE2 engine is used to experimentally study the swirl variation for different openings of the valve. The sliding of the swirl plate results in the variation of the area of inlet port entry. Therefore in this study a swirl optimized combustion system varying according to the operating conditions by a variable swirl plate mechanism is studied experimentally and compared with the computational fluid dynamics predictions. In this study the fluent computational fluid dynamics code has been used to evaluate the flow in the port-cylinder system of a DI diesel engine in a steady flow rig. The computational grid is generated directly from 3-D CAD data and in cylinder flow simulations, with inflow boundary conditions from experimental measurements, are made using the fluent computational fluid dynamics code. The results are in very good agreement with experimental results.

Metal Temperature Prediction of a Dry Low NOx Class Flame Tube by Computational Fluid Dynamics Conjugate Heat Transfer Approach

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Antonio Andreini ◽  
Lorenzo Mazzei ◽  
Giovanni Riccio ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Operating Conditions ◽  
Metal Temperature ◽  
Thermal Loads ◽  
Flame Tube ◽  
Numerical Predictions ◽  
Partial Load ◽  
Critical Components

Combustor liner of present gas turbine engines is subjected to high thermal loads as it surrounds high temperature combustion reactants and is hence facing the related radiative load. This generally produces high thermal stress levels on the liner, strongly limiting its life expectations and making it one of the most critical components of the entire engine. The reliable prediction of such thermal loads is hence a crucial aspect to increase the flame tube life span and to ensure safe operations. The present study aims at investigating the aerothermal behavior of a GE Dry Low NOx (DLN1) class flame tube and in particular at evaluating working metal temperatures of the liner in relation to the flow and heat transfer state inside and outside the combustion chamber. Three different operating conditions have been accounted for (i.e., lean–lean partial load, premixed full load, and primary load) to determine the amount of heat transfer from the gas to the liner by means of computational fluid dynamics (CFD). The numerical predictions have been compared to experimental measurements of metal temperature showing a good agreement between CFD and experiments.

scholarly journals A zonal approach for estimating pressure ratio at compressor extreme off-design conditions

2018 ◽  
Vol 20 (4) ◽  
pp. 393-404 ◽  
Author(s):  
José Galindo ◽  
Roberto Navarro ◽  
Luis Miguel García-Cuevas ◽  
Daniel Tarí ◽  
Hadi Tartoussi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Pressure Ratio ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Combustion Engines ◽  
One Dimensional ◽  
Performance Map

Zero-dimensional/one-dimensional computational fluid dynamics codes are used to simulate the performance of complete internal combustion engines. In such codes, the operation of a turbocharger compressor is usually addressed employing its performance map. However, simulation of engine transients may drive the compressor to work at operating conditions outside the region provided by the manufacturer map. Therefore, a method is required to extrapolate the performance map to extended off-design conditions. This work examines several extrapolating methods at the different off-design regions, namely, low-pressure ratio zone, low-speed zone and high-speed zone. The accuracy of the methods is assessed with the aid of compressor extreme off-design measurements. In this way, the best method is selected for each region and the manufacturer map is used in design conditions, resulting in a zonal extrapolating approach aiming to preserve accuracy. The transitions between extrapolated zones are corrected, avoiding discontinuities and instabilities.

Application of computational fluid dynamics for thermohydrodynamic analysis of high-speed squeeze-film dampers

2019 ◽  
Vol 43 (3) ◽  
pp. 306-321 ◽  
Author(s):  
Maxime Perreault ◽  
Sina Hamzehlouia ◽  
Kamran Behdinan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Base Line ◽  
Squeeze Film Dampers ◽  
Shaft Deflection ◽  
Whirl Speed

In high-speed turbomachinery, the presence of rotor vibrations, which produce undesirable noise or shaft deflection and losses in performance, has brought up the need for the application of a proper mechanism to attenuate the vibration amplitudes. Squeeze-film dampers (SFDs) are a widely employed solution to the steady-state vibrations in high-speed turbomachinery. SFDs contain a thin film of lubricant that is susceptible to changes in temperature. For this reason, the analysis of thermohydrodynamic (THD) effects on the SFD damping properties is essential. This paper develops a computational fluid dynamics (CFD) model to analyze the THD effects in SFDs, and enabling the application of CFD analysis to be a base-line for validating the accuracy of analytical THD SFD models. Specifically, the CFD results are compared against numerical simulations at different operating conditions, including eccentricity ratios and journal whirl speeds. The comparisons demonstrate the effective application of CFD for THD analysis of SFDs. Additionally, the effect of the lubricant THDs on the viscosity, maximum and mass-averaged temperature, as well as heat generation rates inside the SFD lubricant are analyzed. The temperature of the lubricant is seen to rise with increasing whirl speed, eccentricity ratios, damper radial clearance, and shaft radii.

scholarly journals Development of an optical swirl sensor for DI-diesel engines

2009 ◽  
Vol 137 (2) ◽  
pp. 37-49
Author(s):  
Robin VANHAELST ◽  
Werner HENTSCHEL ◽  
Christian MÜLLER ◽  
Jakub CZAJKA
Keyword(s):  
Diesel Engine ◽  
Optical Sensor ◽  
High Speed ◽  
Swirling Flow ◽  
Combustion Process ◽  
Optical Probe ◽  
Swirl Ratio ◽  
Acceptance Angle ◽  
Di Diesel Engine ◽  
Dimensional Simulation

In this paper the systematic development of an optical swirl sensor to measure the swirl ratio in an operating serial turbocharged DI-diesel engine is described. The optical sensor detects the visible light of the combustion, in particular the emission of the sooting flame in a wavelength range from 600 nm up to 1000 nm. The acceptance angle is so small that the soot clouds from every spray can be detected as they are being turned under the optical sensor by the swirling flow. In a first part the new optical probe method was validated on a transparent engine by comparison with high speed video recordings. In the second part several hardware variations were made on a serial DI-diesel engine which was equipped with a variable swirl valve. The influence of the opened- and closed swirl valve constellation and the piston geometry on the swirl ratio was measured with the optical probe technique. The results were compared with a zero dimensional simulation model. There was a good agreement between the swirl measurements and the 0D-model. The optical swirl sensor has proven to be a powerful tool to optimise the combustion process. Without any modifications on the cylinder head, the effect of application parameters and hardware parts on the swirl strength can be quantified for all engine loads and speeds.

scholarly journals Development of an optical swirl sensor for DI-diesel engines

2010 ◽  
Vol 143 (4) ◽  
pp. 45-59
Author(s):  
Robin VANHAELST ◽  
Jakub CZAJKA
Keyword(s):  
Diesel Engine ◽  
Optical Sensor ◽  
High Speed ◽  
Swirling Flow ◽  
Combustion Process ◽  
Optical Probe ◽  
Swirl Ratio ◽  
Acceptance Angle ◽  
Di Diesel Engine ◽  
Dimensional Simulation

In this paper the systematic development of an optical swirl sensor to measure the swirl ratio in an operating serial turbocharged DI-diesel engine is described. The optical sensor detects the visible light of the combustion, in particular the emission of the sooting flame in a wavelength range from 600 nm up to 1000 nm. The acceptance angle is so small that the soot clouds from every spray can be detected as they are beeing turned under the optical sensor by the swirling flow. In a first part the new optical probe method was validated on a transparent engine by comparison with high speed video recordings. In the second part several hardware variations were made on a serial DI-diesel engine which was equipped with a variable swirl valve. The influence of the opened- and closed swirl valve constellation, the piston geometry and the injector influence on the swirl ratio was measured with the optical probe technique. The results were compared with a zero dimensional simulation model. There was a good agreement between the swirl measurements and the 0D-model. The optical swirl sensor has proven to be a powerful tool to optimise the combustion process. Without any modifications on the cylinder head, the effect of application parameters and hardware parts on the swirl strength can be quantified for all engine loads and speeds.

Effect of Intake Port Bend Angle on Flow Field Inside the Cylinder of a DI Diesel Engine

2007 ◽  
Author(s):  
B. Jayashankara ◽  
V. Ganesan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Diesel Engine ◽  
Flow Field ◽  
Design Tool ◽  
Turbulent Intensity ◽  
Cfd Modeling ◽  
Bend Angle ◽  
Intake Port ◽  
Di Diesel Engine

This paper presents the computational fluid dynamics (CFD) modeling to study the effect of intake port bend angle on the flow field inside the cylinder of a direct injection (DI) diesel engine under motoring conditions. The flow characteristics of the engine are investigated under transient conditions. A single cylinder DI diesel engine with two direct intake ports whose outlet is tangential to the wall of the cylinder and two exhaust ports has been taken up for the study. Effect of intake port bend angle (20°, 30°, and 40°) on the flow field inside the cylinder has been investigated at an engine speed of 1000 rpm. The pre-processor GAMBIT is used for model preparation and commercial computational fluid dynamics code STAR-CD has been used for solution of governing equations and post processing the results. CFD results during both intake and compression strokes have been compared with experimental results of Payri et-al [7, 8]. The predicted swirl ratio, radial velocity and turbulent intensity variations at different crank angles and at different locations are discussed. Distribution of velocity and turbulence intensity inside the cylinder is also discussed. It is observed that the intake ports with 20° bend angle produce maximum swirl and also results in a slight decrease in volumetric efficiency compared to intake ports with 30° and 40° bend angles and there is no appreciable variation in turbulent intensity. Hence, for the better performance of a DI diesel engine, it is concluded that the intake ports with 20° bend angle is most appropriate and CFD is an effective design tool to develop more efficient DI diesel engines.

1D Engine Simulation of a Small HSDI Diesel Engine Applying a Predictive Combustion Model

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
T. Cerri ◽  
A. Onorati ◽  
E. Mattarelli
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Combustion Model ◽  
Full Load ◽  
Partial Load

The paper analyzes the operations of a small high speed direct injection (HSDI) turbocharged diesel engine by means of a parallel experimental and computational investigation. As far as the numerical approach is concerned, an in-house 1D research code for the simulation of the whole engine system has been enhanced by the introduction of a multizone quasi-dimensional combustion model, tailored for multijet direct injection diesel engines. This model takes into account the most relevant issues of the combustion process: spray development, air-fuel mixing, ignition, and formation of the main pollutant species (nitrogen oxide and particulate). The prediction of the spray basic patterns requires previous knowledge of the fuel injection rate. Since the direct measure of this quantity at each operating condition is not a very practical proceeding, an empirical model has been developed in order to provide reasonably accurate injection laws from a few experimental characteristic curves. The results of the simulation at full load are compared to experiments, showing a good agreement on brake performance and emissions. Furthermore, the combustion model tuned at full load has been applied to the analysis of some operating conditions at partial load, without any change to the calibration parameters. Still, the numerical simulation provided results that qualitatively agree with experiments.

Computational fluid dynamics study of the effects of the re-entrant lip shape and toroidal radii of piston bowl on a high-speed direct-injection diesel engine's performance and emissions

2005 ◽  
Vol 219 (8) ◽  
pp. 1011-1023 ◽  
Author(s):  
Y Zhu ◽  
H Zhao ◽  
N Ladommatos
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Injection System ◽  
Part Load ◽  
Piston Bowl

The piston bowl design is one of the most important factors that affect the air-fuel mixing and the subsequent combustion and pollutant formation processes in a direct-injection diesel engine. The bowl geometry and dimensions, such as the pip region, bowl lip area, and toroidal radius, are all known to have an effect on the in-cylinder mixing and combustion process. In order to understand better the effect of re-entrant geometry, three piston bowls with different toroidal radii and lip shapes were investigated using computational fluid dynamics engine modelling. KIVA3V with improved submodels was used to model the in-cylinder flows and combustion process, and it was validated on a high-speed direct-injection engine with a second-generation common-rail fuel injection system. The engine's performance, in-cylinder flow, and combustion, and emission characteristics were analysed at maximum power and maximum torque conditions and at part-load operating conditions. Three injector protrusions and injection timings were investigated at full-load and part-load conditions.

Simulation and Experimental Investigation of Variable Swirl Intake Port in DI Diesel Engine Using CFD

2006 ◽  
Author(s):  
J. David Rathnaraj ◽  
B. Jefferson Raja Bose ◽  
Michael N. Kumar
Keyword(s):  
Fluid Dynamics ◽  
Diesel Engine ◽  
Flow Field ◽  
Diesel Engines ◽  
Experimental Validation ◽  
Swirl Flow ◽  
Intake Port ◽  
Swirl Ratio ◽  
Port Design ◽  
Di Diesel Engine

Knowledge of the flow phenomena inside the cylinder is necessary for optimum design of the intake port and the piston cavity configurations. Recent trends in direct injection diesel engines have increased the need for clear understanding of the flow field, especially the swirl characteristics. The swirl flow is an essential parameter which affects the air fuel mixing, combustion efficiency and therefore the engine performance. The purpose of this study is to investigate the combustion, emission, spray and flow field phenomena of a D I diesel engine and to come up with a geometrical shape for a port and valve or valves that produce the optimum swirl ratio. The percentage opening of a helical port for the DI diesel engine is simulated and studied using Computational Fluid Dynamics with experimental validation. Steady flow rig experiments are most widely used to evaluate the swirl ratio of an intake port design. The three dimensional developing flow patterns are needed throughout the compression and combustion stroke to understand the various experimental results. Flow is simulated by solving governing equations, viz., conservation of mass and momentum using the simple-algorithm. Turbulence has been modeled by standard kφ–φ∈ model with standard wall treatment. The predictive accuracy of the calculation method is compared with detailed mass flow rate and paddle rpm measurements. The results are in good agreement with experimental results and clearly predict the under predictability of the paddle swirl meter in lower lifts. Emission standards, which demand large reduction in NOx and PM emission, require a more comprehensive study of all elements that contribute to emission formulation. The combustion chamber is subject of research and development in an effort to achieve optimized combustion system. The intake port fluid dynamics contribute to the fuel air mixing which in turn is the most important parameter for the control of fuel burning rate for diesel engines. The intake port fluid dynamics also significantly affects ignition delay, the magnitude and timing of the diffusion burn, the magnitude of the premixed burn and emission of nitrous oxide and soot. According to the Modulated Kinetics (MK) concept, which improves the emission performance of diesel engines, a D I Diesel engine requires higher intake swirl in the part-load region. The computations are used to optimize the swirl flow characteristics of an intake port system over a wide range of operating conditions. In this study, the numerical simulation of the helical intake port and variable swirl intake port for two-valve DI Diesel engines are discussed with experimental validation. The improvement of swirl generation capacity of the port design according to the stringent emission norms are also studied.

Sign in / Sign up

Export Citation Format

Share Document