An Experimental Data Base for the Computational Fluid Dynamics of Combustors

1989 ◽  
Vol 111 (1) ◽  
pp. 11-14 ◽  
Author(s):  
R. E. Charles ◽  
G. S. Samuelsen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Data Base ◽  
Recirculation Zone ◽  
Fuel Injection ◽  
Thermal Structure ◽  
Injection Angle ◽  
Laser Anemometry ◽  
Inlet Geometry ◽  
Type R Thermocouple

A model axisymmetric gas-fired can combustor is used to (1) establish the sensitivity of the aerodynamic and thermal structure to inlet boundary conditions, and (2) thereby establish a demanding and comprehensive data base for the computational fluid dynamics of combustors. The parameters varied include fuel injection angle and inlet configuration. Detailed characterizations of the aerodynamic and thermal flowfields are accomplished using two-color laser anemometry and a Type R thermocouple, respectively. Specific results show that the reactor operation is especially sensitive to modest changes in both the inlet geometry and fuel injection angle. For example, the addition of a step expansion significantly alters the size and location of the swirl-induced toroidal recirculation zone. Further, the use of the step expansion, in combination with the injection of fuel matched to the swirl aerodynamics, transforms the recirculation zone to an on-axis structure. The addition of a divergent inlet further enhances the effectiveness of the backmixing by enlarging the recirculation zone. The data base developed for these conditions is carefully documented and provides a comprehensive challenge for the computational fluid dynamics of combustors.

The influence of the enrichment injection angle on the performance of a pre-chamber spark ignition natural-gas engine

2017 ◽  
Vol 232 (5) ◽  
pp. 679-694 ◽  
Author(s):  
Liyan Feng ◽  
Jun Zhai ◽  
Chuang Qu ◽  
Bo Li ◽  
Jiangping Tian ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Gas ◽  
Nitrogen Oxide ◽  
Spark Ignition ◽  
Nitrogen Oxide Emissions ◽  
Mixture Formation ◽  
Injection Angle ◽  
Gas Engine ◽  
Natural Gas Engine

Using an enriched pre-chamber is an effective way to extend the lean limit, to reduce the nitrogen oxide emissions and to avoid abnormal combustion in spark ignition natural-gas engines. Enrichment injection in the pre-chamber of a spark ignition natural-gas engine determines the flow field and the fuel–air mixture formation quality in the pre-chamber and has a profound influence on the combustion performance of the engine. In order to study the characteristics of enrichment injection in the pre-chamber of a natural-gas engine, two-dimensional particle image velocimetry measurements and three-dimensional computational fluid dynamics calculations were carried out. The influence of the enrichment injection angle on the engine performance was investigated with the aid of a computational fluid dynamics simulation tool. The results indicate that a change in the enrichment injection angle directly affects the gas motion, the fuel–air mixture formation, the flame propagation and the formation of nitrogen oxides in the pre-chamber and further influences the penetration of the flame jets, the combustion temperature distribution and the formation of nitrogen oxides in the main chamber. There is an optimal injection angle for this research engine. Of the four injection angles that were investigated, an injection angle of 14° results in the lowest nitrogen oxide emissions.

Computational Investigation of the Effects of Piston Geometry on the Combustion Evolution in a Light Duty HSDI Engine

2017 ◽  
Author(s):  
Riyaz Ismail ◽  
Felix Leach ◽  
Martin H. Davy ◽  
David Richardson ◽  
Brian Cooper
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Combustion Chamber ◽  
Adaptive Mesh Refinement ◽  
Fuel Injection ◽  
Temporal Distribution ◽  
Adaptive Mesh ◽  
Test Point ◽  
Piston Bowl ◽  
Dynamics Simulations

The spatial and temporal distribution of fuel and air within the combustion chamber directly influences ignition, combustion and emissions formation in diesel engines. These fuel-air interactions are affected by details of the combustion chamber geometry and fuel injection parameters. This paper investigates the effects of piston bowl geometry and spray targeting on combustion behaviour in a single cylinder diesel engine. Closed cycle computational fluid dynamics simulations are performed on a sector mesh at various load points using the 3 Zones Extended Coherent Flame Model coupled with adaptive mesh refinement. The computational fluid dynamics model is validated experimentally at the baseline conditions at each test point after-which, parametric sweeps of bowl geometry, exhaust gas recirculation rate and nozzle tip protrusion are conducted. Results indicate that appropriately pairing fuel injection strategy and piston geometry is essential.

Experimental and Computational Analyses of Methane and Hydrogen Mixing in a Model Premixer

2011 ◽  
Vol 133 (10) ◽  
Author(s):  
Amin Akbari ◽  
Scott Hill ◽  
Vincent McDonell ◽  
Scott Samuelsen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Schmidt Number ◽  
Fuel Injection ◽  
Agricultural Waste ◽  
Flux Ratio ◽  
Systematic Evaluation ◽  
Efficient Design ◽  
Efficient Manner ◽  
Turbulent Schmidt Number

The mixing of fuel and air in combustion systems plays a key role in overall operability and emissions performance. Such systems are also being looked to for operation on a wide array of potential fuel types, including those derived from renewable sources such as biomass or agricultural waste. The optimization of premixers for such systems is greatly enhanced if efficient design tools can be utilized. The increased capability of computational systems has allowed tools such as computational fluid dynamics to be regularly used for such purpose. However, to be applied with confidence, validation is required. In the present work, a systematic evaluation of fuel mixing in a specific geometry, which entails cross flow fuel injection into axial nonswirling air streams has been carried out for methane and hydrogen. Fuel concentration is measured at different planes downstream of the point of injection. In parallel, different computational fluid dynamics approaches are used to predict the concentration fields resulting from the mixing of fuel and air. Different steady turbulence models including variants of Reynolds averaged Navier–Stokes (RANS) have been applied. In addition, unsteady RANS and large eddy simulation are used. To accomplish mass transport with any of the RANS approaches, the concept of the turbulent Schmidt number is generally used. As a result, the sensitivity of the RANS simulations to different turbulent Schmidt number values is also examined. In general, the results show that the Reynolds stress model, with use of an appropriate turbulent Schmidt number for the fuel used, provides the best agreement with the measured values of the variation in fuel distribution over a given plane in a relatively time efficient manner. It is also found that, for a fixed momentum flux ratio, both hydrogen and methane penetrate and disperse in a similar manner for the flow field studied despite their significant differences in density and diffusivity.

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.

scholarly journals Optimization of critical angle, distance and flow rate of secondary fuel injection in DI diesel engine using computational fluid dynamics

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
M. Sonachalam ◽  
V. Manieniyan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Fuel Injection ◽  
Combustion Process ◽  
Superior Performance ◽  
Intake Manifold ◽  
Fuel Injector ◽  
Performance And Emission ◽  
Secondary Fuel

AbstractThis study presents the optimization of the intake manifold and the optimized flow rate of the acetylene gas which acts as a low reactivity fuel to achieve the superior performance and emission characteristics used in the Reactivity controlled compression ignition (RCCI) engine. Intake manifold is one of the engine components which are an important factor in determining the quality of combustion. A very recent evolution of the RCCI engine using the low temperature combustion technique requires a low reactivity fuel which is injected through the secondary fuel injector. The secondary fuel injector must be designed and optimized to allow the acetylene gas to maximize the engine performance and the amount of acetylene gas in liters per minute required for better combustion. If the secondary fuel injector is mounted apart from the critical point, then the performance of the RCCI engine may be poor and also if the acetylene gas is not supplied properly, there is a risk of poor combustion and also if the acetylene gas is supplied excessively, there is a risk of knocking along with the backfire due to the excess fuel charge accumulation during the combustion process. Physical testing of the secondary fuel injector in the intake manifold with different angles, distance and flow rate of supply of acetylene gas is time and cost consuming process. To mitigate this issue optimization is done through computational fluid dynamics principles comes in handy to minimize time and money. In our study, ANSYS-FLUENT software is used for simulation purposes. Optimization of acetylene gas injector distance is carried out by analyzing the pressure contours at the entrance of the combustion chamber. The optimized flow rate of acetylene gas and the injector inclination is found by analyzing the flow contours of turbulent kinetic energy and turbulent dissipation rate.

scholarly journals Computational Fluid Dynamics (CFD)-Based Optimization of Injection Process during Endoscopic Mucosal Therapy

2020 ◽  
Vol 7 (4) ◽  
pp. 136
Author(s):  
Mohamad Aghaie Meybodi ◽  
Rohit Saini ◽  
Amirfarhang Mehdizadeh ◽  
Reza Hejazi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Muscle Layer ◽  
Effect Of Temperature ◽  
Injection Technique ◽  
Continuous Change ◽  
Injection Angle ◽  
Injection Process ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact

Creation of a submucosal plane to separate the lesion from the deeper muscle layer in gastrointestinal tract is an integral and essential part of endoscopic resection therapies such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). Thereby, an optimized submucosal injection technique is required to ensure a successful process. In this study, the computational fluid dynamics (CFD) technique is employed as a foundational step towards the development of a framework that can provide useful directions to optimize the injection process. Three different lifting agents, including Glycerol, Eleview®, and ORISE® gel have been used for this study. The role of different injection angles, injection dynamics, and effect of temperature are studied to understand the lifting characteristic of each agent. The study shows that Eleview® provides the highest lifting effect, including the initial injection period. To evaluate the impact of the injection process, two cases are simulated, termed static injection and dynamic injection. Under static injection, the injection angle is investigated from lower to higher angles of injection. In the dynamic injection, two cases are modulated, where a continuous change of injection angle from lower to higher degrees (denoted as clockwise) and vice-versa in the anti-clockwise direction are investigated. Increased lifting characteristics are observed at decreasing/lower angle of injection. Further, the correlation between temperature of the lifting agents and their lifting characteristics is investigated.

Computational Fluid Dynamics of Liquid and Foam Sclerosant Injection in a Vein Model

2014 ◽  
Vol 553 ◽  
pp. 293-298 ◽  
Author(s):  
Kai Chung Wong ◽  
Tony Chen ◽  
David E. Connor ◽  
Masud Behnia ◽  
Kurosh Parsi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Modelling ◽  
Injection Velocity ◽  
Complex Nature ◽  
Good Representation ◽  
Limited Information ◽  
Cfd Model ◽  
Cfd Modelling ◽  
Injection Angle

The aim of this study was to develop a computational fluid dynamics (CFD) model to simulate the injection of liquid and foam sclerosants into a varicose vein. The CFD model results were compared with sclerosant flow in an experimental model of a straight or a branched vein. The effects of injection angle, injection velocity and tubing contents (blood, saline) on sclerosant spreading were assessed by CFD. The simulation of liquid sclerosants injection was able to provide a good representation of forward flow, but underrepresented sclerosant backflow. Due to the complex nature of computational modelling of foams, CFD modelling of foam sclerosants injection was less accurate and provided only limited information on foam spreading. CFD modelling can be used as a representation of liquid and foam sclerosant injection, but further research is required to provide a more accurate analysis.

scholarly journals Validation of a Grid Independent Spray Model and Fuel Chemistry Mechanism for Low Temperature Diesel Combustion

2009 ◽  
Vol 1 (3) ◽  
pp. 283-316 ◽  
Author(s):  
Takeshi Yoshikawa ◽  
Rolf D. Reitz
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Low Temperature ◽  
Fuel Injection ◽  
Fuel Spray ◽  
Computational Time ◽  
Low Temperature Combustion ◽  
Computational Mesh ◽  
Temperature Combustion ◽  
Computational Fluid Dynamics Cfd

Spray and combustion submodels used in a Computational Fluid Dynamics (CFD) code, KIVACHEMKIN, were validated for Low Temperature Combustion (LTC) in a diesel engine by comparing measured and model predicted fuel spray penetrations, and in-cylinder distributions of OH and soot. The conditions considered were long ignition delay, early and late fuel injection cases. It was found that use of a grid independent spray model, called the GASJET model, with an improved n-heptane chemistry mechanism can well predict the heat release rate, not only of the main combustion stage, but also of the cool flame stage. Additionally, the GASJET model appropriately predicts the distributions of OH and soot in the cylinder even when the resolution of the computational mesh is decreased by half, which significantly reduces the required computational time.

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