In-cylinder Airflow Characteristics Research Articles

Numerical Investigation of the Effect of Incorporated Guide Vane Length with SCC Piston for High-Viscosity Fuel Applications

Compression ignition (CI) engines that run on high-viscosity fuels (HVF) like emulsified biofuels generally demonstrate poor engine performance. An engine with a consistently low performance, in the long run, will have a negative effect on its lifespan. Poor combustion in engines occurs mainly due to the production of less volatile, less flammable, denser, and heavier molecules of HVF during injection. This paper proposes a guide vane design (GVD) to be installed at the intake manifold, which is incorporated with a shallow depth re-entrance combustion chamber (SCC) piston. This minor modification will be advantageous in improving the evaporation, diffusion, and combustion processes in the engine to further enhance its performance. The CAD models of the GVD and SCC piston were designed using SolidWorks 2018 while the flow run analysis of the cold flow CI engine was conducted using ANSYS Fluent Version 15. In this study, five designs of the GVD with varying lengths of the vanes from 0.6D (L) to 3.0D (L) were numerically evaluated. The GVD design with 0.6D (L) demonstrated improved turbulence kinetic energy (TKE) as well as swirl (Rs), tumble (RT), and cross tumble (RCT) ratios in the fuel-injected zone compared to other designs. The suggested improvements in the design would enhance the in-cylinder airflow characteristics and would be able to break up the penetration length of injection to mix in the wider area of the piston-bowl.

Numerical Investigation of Fluid Flow and In-Cylinder Air Flow Characteristics for Higher Viscosity Fuel Applications

Generally, the compression ignition (CI) engine that runs with emulsified biofuel (EB) or higher viscosity fuel experiences inferior performance and a higher emission compared to petro diesel engines. The modification is necessary to standard engine level in order to realize its application. This paper proposes a guide vane design (GVD), which needs to be installed in the intake manifold, is incorporated with shallow depth re-entrance combustion chamber (SCC) pistons. This will organize and develop proper in-cylinder airflow to promote better diffusion, evaporation and combustion processes. The model of GVD and SCC piston was designed using SolidWorks 2017; while ANSYS Fluent version 15 was utilized to run a 3D analysis of the cold flow IC engine. In this research, seven designs of GVD with the number of vanes varied from two to eight vanes (V2–V8) are used. The four-vane model (V4) has shown an excellent turbulent flow as well as swirl, tumble and cross tumble ratios in the fuel-injected region compared to other designs. This is indispensable to break up heavier fuel molecules of EB to mix with the air that will eventually improve engine performance.

Effect of Vane Numbers on the In-Cylinder Air Flow Characteristic in Compression Ignition (CI) Engine Run with Emulsified Biofuel

Abstract The inferior performance and certain higher emissions produced from compression ignition (CI) engine through contemporary biological process such as biofuel is more severe compared to geological process such as petro-diesel. In this study, the design on the guide vane design (GVD) preferably on the number of vanes; 3 to 5, where it was mounted in front of the intake manifold is investigated in order to tackle those issues mentioned. It was run with emulsified biofuel (EB) and the GVD with fixed of vane high, angle and length to enhance the in-cylinder air flow characteristics; by right the diffusion, evaporation and combustion process can be improved. It was found that the 4 vanes with angles of 35°, vane height of 0.2R and length three times the radius of the intake manifold respectively has a superiority results in turbulence kinetic energy (TKE) and swirl ratio.

Numerical investigation of in-cylinder air flow characteristic improvement for Emulsified biofuel (EB) application

Abstract Emulsified biofuel (EB) has a relatively higher viscosity compared to conventional diesel; which affects the spray injection and restricts the maximum evaporation. The modification is necessary to standard engines in order to realize its application. This paper presents the effects of three dissimilar designs of piston-bowl geometry in the compression ignition (CI) engine to in-cylinder airflow characteristics improvement of the EB during injection. The three piston bowl geometry designs; open cylinder bowl (OCB), shallow depth re-entrance combustion chamber (SCC) and omega combustion chamber (OCC). ANSYS FLUENT 15 is utilized to run a three dimensional (3D) cold flow internal combustion (IC) engine simulation. The main parameters of this investigation; swirl, tumble and cross tumble ratios, as well as turbulence kinetic energy (TKE), with respect to crank angle. It shows that the SCC piston bowl design is the best due to significant effect on swirl, tumble, cross tumble ratios and TKE in the injection fuel region. It breaks up the length penetration of injection to mix with the surrounding air and capable to organize the distribution of the heavier molecules of the EB during the compression stage.

In-cylinder air-flow characteristics of different intake port geometries using tomographic PIV

For improving the in-cylinder flow characteristics of intake air/charge and for strengthening the turbulence intensity, specific intake port geometries have shown significant potential in compression ignition engines. In this experimental study, effects of intake port geometries on air-flow characteristics were investigated using tomographic particle imaging velocimetry (TPIV). Experiments were performed using three experimental conditions, namely, swirl port open (SPO), tangential port open (TPO), and both port open (BPO) configurations in a single cylinder optical research engine. Flow investigations were carried out in a volumetric section located in the middle of the intake and exhaust valves. Particle imaging velocimetry (PIV) images were captured using two high speed cameras at a crank angle resolution of 2° in the intake and compression strokes. The captured PIV images were then pre-processed and post-processed to obtain the final air-flow-field. Effects of these two intake ports on flow-field are presented for air velocity, vorticity, average absolute velocity, and turbulent kinetic energy. Analysis of these flow-fields suggests the dominating nature of the swirl port over the tangential port for the BPO configuration and higher rate of flow energy dissipation for the TPO configuration compared to the SPO and BPO configurations. These findings of TPIV investigations were experimentally verified by combustion and particulate characteristics of the test engine in thermal cylinder head configuration. Combustion results showed that the SPO configuration resulted in superior combustion amongst all three port configurations. Particulate characteristics showed that the TPO configuration resulted in higher particulate compared to other port configurations.

Numerical study on dissimilar guide vane design with SCC piston for air and emulsified biofuel mixing improvement

Crude palm oil (CPO) is one of the most potential biofuels that can be applied in the conventional diesel engines, where the chemical properties of CPO are comparable to diesel fuel. However, its higher viscosity and heavier molecules can contributes to several engine problems such as low atomization during injection, carbon deposit formation, injector clogging, low mixing with air and lower combustion efficiency. An emulsification of biofuel and modifications of few engine critical components have been identified to mitigate the issues. This paper presents the effects of dissimilar guide vane design (GVD) in terms of height variation of 0.25 R , 0.3 R and 0.35 R at the intake manifold with shallow depth re-entrance combustion chamber (SCC) piston application to the incylinder air flow characteristics improvement. The simulation results show that the intake manifold with GVD improved the performance of the air flow characteristic particularly swirl, tumble and cross tumble ratios from the intake manifold to the engine. The GVD with the height of 0.3 R was found to be the optimum design with respect to the overall improvement of the air flow characteristic. The improvement of the air flow characteristic with the application of GVD and SCC piston in the engine was expected to contribute to a better air fuel mixing, fuel atomization and combustion efficiency of the engine using emulsified biofuel as a source of fuel.

Simulation and Experimental Investigation of Guide Vane Length to Improve the Performance of a Diesel Engine Run With Biodiesel

This research investigated the effect of guide vanes into the intake runner of a diesel engine run with higher viscous biodiesel to enhance the in-cylinder intake airflow characteristics. First, simulation of an internal combustion engine base model was done. Guide vanes of various lengths were developed and imposed into the intake runner to investigate the airflow characteristics. Based on the simulation results, five guide vanes models of 8, 10, 12, 14, and 16 mm length were constructed and tested on a compression ignition (CI) engine run with biodiesel. According to the experimental results of engine performance and emissions, it was found that guide vanes of 12 mm length showed the highest number of improvements with 14 mm and 10 mm length showed the second and third highest number of improvements, respectively. Therefore, this research concluded that guide vanes successfully improved the in-cylinder air flow characteristics to improve the mixing of higher viscous biodiesel with air resulting in better performances of the engines than without vanes.

Optimization of vane numbers through simulation and experiment, and investigation of the effect on the performance and emissions of a CI (compression ignition) engine run with biodiesel

Generally, the CI (compression ignition) engine that runs with biodiesel experiences lower performance and certain higher emissions than the one that runs with petro-diesel. For that reason, this research investigated the effect of guide vanes installed in front of the intake manifold of a CI engine run with biodiesel to enhance the in-cylinder airflow to promote the evaporation, diffusion, and combustion processes to eventually reduce those problems. This research began with optimizing the design of the guide vanes through the simulation method. However, the optimization was limited only to the number of guide vanes while vane height, angle, and length were kept constant. After analyzing the simulation results of in-cylinder airflow characteristics of TKE (turbulence kinetic energy), velocity, vorticity, and swirling strength of 10 guide vanes models of different vane numbers that varied in between 3 and 12, the model with 4 vanes was found to be the optimum one. After that, five guide vanes models with the number of vanes ranging between 3 and 7 were fabricated and tested one by one on a CI engine run with biodiesel along with a standard CI engine run with biodiesel and petro-diesel having no vanes. Based on the simulations and experimental results, 4 vanes were found to be the optimum number with vane angles of 35° along with vane height and length of 0.2 and three times the radius of the intake runner, respectively.

Guide Vane Swirl and Tumble Device to Improve in-cylinder Air Flow of CI Engine Using Vegetable Oil

A guide vane swirl and tumble device (GVSTD) can be used in compression ignition (CI) engines running on vegetable oils to generate better in-cylinder air flow characteristics to improve combustion efficiency. In this paper, IC engine simulations were performed to determine the effect of GVSTD on the air flow using 3D computational fluid dynamics (CFD) software. The effects of various vane heights by means of parametric optimization were investigated. The results of average in-cylinder pressure, turbulent kinetic energy (TKE) and velocity were analyzed before the optimum vane height to the pre-set values of vane angle, number and length were decided. Interestingly, the highest vane height failed to improve all the analyzed parameters. At a GVSTD vane height of 0.2 times the intake runner radius, the average in-cylinder pressure, TKE and velocity were found better than with other settings.

CFD modelling of the effect of guide vane swirl and tumble device to generate better in-cylinder air flow in a CI engine fuelled by biodiesel

The demand for alternative fuels has increased since the recession of crude oil and environmental pollutions have become the main concerns in automotive industry. Biodiesel is seen as the primary selection in this category as it is renewable and able to mitigate the world production of greenhouse gas CO2. However, biodiesel has a higher viscosity compared to conventional diesel, consequently making it less susceptible to evaporation since the fuel molecules are heavier and move slower than diesel. This paper proposes that a Guide Vane Swirl and Tumble Device (GVSTD) be installed in front of the intake port to develop an organized turbulence to assist in the breakup of fuel molecules for improved mixing with air. To investigate the effect of GVSTD to generate better in-cylinder air flow, ANSYS-CFX was used to run a 3D cold flow IC engine simulation. The model was validated with the experimental results of in-cylinder pressure from 0°CA to 540°CA and the results of in-cylinder airflow characteristics from simulations were compared with other related research works. In this research, three designs of the GVSTD with the height of the vanes varied at 0.25R, 0.50R and 0.75R, where R is the radius of the intake runner, were compared with the model without GVSTD to investigate its effect on the air flow inside the combustion chamber. The results showed that the 0.25R guide vanes created more turbulence, in-cylinder velocity, swirl and tumble in the injected fuel region than the other designs, which is needed to break up the fuel molecules to mix with air that will eventually improve the engine performance with biodiesel. The resistance to the air flow due to the vanes was also least for the 0.25R guide vanes.

In-Cylinder Air Flow Characteristics Generated by Guide Vane Swirl and Tumble Device to Improve Air-Fuel Mixing in Diesel Engine Using Biodiesel

In order to improve a naturally aspirated (NA) Compression Ignition (CI) engine operating on biodiesel fuel, this research proposes a Guide Vane Swirl and Tumble Device (GVSTD) inside the intake runner of a HINO W04D diesel engine to improve the in-cylinder air flow characteristic as an alternative solution to supplement existing techniques. When the air intake was guided in front of the intake port, organized turbulent air was generated, consequently assisting the fuel to evaporate and mix to produce better combustion and eventually produce better performance. To examine the effectiveness of the GVSTD, a 3D IC engine simulation model was developed. Additionally, this paper also investigates the optimal vane height of GVSTD of four vanes which twist at 35° clockwise direction and are arranged perpendicular to each other with the length of the vanes three times that of the intake radius. Ten simulation models of the GVSTD, where the vane height varied from 10% to 100% of the intake radius were prepared. The simulation results of in-cylinder pressure, turbulence kinetic energy and velocity of the base and all GVSTD models were then compared. The results illustrate a promising improvement of the in-cylinder air flow characteristics inside the fuel injected region by utilizing 20% vane height compared to standard model.