Influence of Injection Pressure Fluctuations on Cavitation inside a Nozzle Hole at Diesel Engine Conditions

2008 ◽  
Author(s):  
Xiang Wang ◽  
Wanhua Su
Keyword(s):  
Diesel Engine ◽  
Pressure Fluctuations ◽  
Injection Pressure ◽  
Nozzle Hole

Modelling and CFD Simulation of Effects of Spray Penetration on Piston Bowl Impingement in a DI Diesel Engine for Biodiesel-Diesel Blend (B20)

2012 ◽  
Author(s):  
Subhash Lahane ◽  
K. A. Subramanian
Keyword(s):  
Diesel Engine ◽  
Cfd Simulation ◽  
Injection Pressure ◽  
Spray Penetration ◽  
Penetration Distance ◽  
Piston Bowl ◽  
Fuel Jet ◽  
Wall Impingement ◽  
Di Diesel Engine ◽  
Nozzle Hole

The effect of spray penetration distance on fuel impingement on piston bowl of a 7.4 kW diesel engine for biodiesel-diesel blend (B20) was studied using modeling and CFD simulation. As the peak inline fuel pressure increased from 460 bar with base diesel to 480 bar with B20, the spray penetration distance (fuel jet) increases. It is observed from the study that the jet tip hits on piston bowl resulting to fuel impingement which is one of durability issues for use of biodiesel blend in the diesel engine. In addition to this, the simulation of effects of different injection pressures up to 2000 bar on spray penetration distance and wall impingement were also studied. The penetration distance increases with increase the in-line fuel pressure and it decreases with decrease nozzle hole diameter. The fuel impingement on piston bowl of the engine with high injection pressure (typically 1800 bar) can be avoided by decreasing the nozzle diameter from 0.19 mm to 0.1 mm. Increase in swirl ratio could also reduce fuel impingement problem.

scholarly journals Effects of injection pressure on cavitation and spray in marine diesel engine

2016 ◽  
Vol 9 (3) ◽  
pp. 186-198 ◽  
Author(s):  
Fei Yan ◽  
Yuchen Du ◽  
Lihui Wang ◽  
Wenxian Tang ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Bubble Dynamics ◽  
Pressure Fluctuations ◽  
Injection Pressure ◽  
Spray Angle ◽  
Marine Diesel Engine ◽  
Sauter Mean Diameter ◽  
Two Phase ◽  
Marine Diesel ◽  
Single Bubble Dynamics

Numerical simulation of the cavitation and spray in a marine diesel engine is performed to investigate the effects of injection pressure on the cavitation flow and spray characteristics in the marine diesel engine, which in turn influence atomization and combustion in the cylinder. A two-phase flow model combined with single bubble dynamics and a droplet break-up model are used to simulate cavitation and spray, respectively, and the results are compared to the experimental data. With increasing injection pressure, the pressure fluctuations inside the nozzle become more intense. The spray penetration is proportional to time at the beginning of injection. Higher injection pressure increases the spray angle. In addition, massive structures on spray edge can return to the spray body, whereas the massive structures on the spray head remain unchanged throughout its lifetime. Each additional 20 MPa of injection pressure reduces the Sauter mean diameter by approximately 9%.

scholarly journals Numerical investigation of injection parameters and piston bowl geometries on emission and thermal performance of DI diesel engine

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Ikhtedar Husain Rizvi ◽  
Rajesh Gupta
Keyword(s):  
Diesel Engine ◽  
Thermal Performance ◽  
Equivalence Ratio ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Injection Nozzle ◽  
Piston Bowl ◽  
Injection Parameters ◽  
Nozzle Size ◽  
Engine Emission

AbstractTightening noose on engine emission norms compelled manufacturers globally to design engines with low emission specially NOx and soot without compromising their performance. Amongst various parameters, shape of piston bowls, injection pressure and nozzle diameter are known to have significant influence over the thermal performance and emission emanating from the engine. This paper investigates the combined effect of fuel injection parameters such as pressure at which fuel is injected and the injection nozzle size along with shape of piston bowl on engine emission and performance. Numerical simulation is carried out using one cylinder naturally aspirated diesel engine using AVL FIRE commercial code. Three geometries of piston bowls with different tumble and swirl characteristics are considered while maintaining the volume of piston bowl, compression ratio, engine speed and fuel injected mass constant along with equal number of variations for injection nozzle size and pressures for this analysis. The investigation corroborates that high swirl and large turbulence kinetic energy (TKE) are crucial for better combustion. TKE and equivalence ratio also increased as the injection pressure increases during the injection period, hence, enhances combustion and reduces soot formation. Increase in nozzle diameter produces higher TKE and equivalence ratio, while CO and soot emission are found to be decreasing and NOx formation to be increasing. Further, optimization is carried out for twenty-seven cases created by combining fuel injection parameters and piston bowl geometries. The case D2H1P1 (H1 = 0.2 mm, P1 = 200 bar) found to be an optimum case because of its lowest emission level with slightly better performance.

Investigations on performance of diesel engine by varying injection timings with design modification on piston crown

2018 ◽  
Vol 15 (5) ◽  
pp. 562-566
Author(s):  
Vijaya K. ◽  
Shailesh Palaparty ◽  
Raghavan Srinivasa ◽  
Ravi Kumar Puli
Keyword(s):  
Diesel Engine ◽  
Injection Pressure ◽  
Combustible Mixture ◽  
Injection Timing ◽  
Connecting Rod ◽  
Design Modification ◽  
Content Type ◽  
Piston Head ◽  
Piston Crown ◽  
Fuel Vaporization

Purpose Investigations are carried out with the aim of improving performance of a diesel engine with the design modification on piston crown to stimulate the uniform combustion by inducing turbulence in the incoming charge. Design/methodology/approach A stirrer is introduced at the top of the piston so as to inculcate more turbulence to the incoming charge by improving the rate of fuel vaporization. Whirling motion is created in the combustible mixture by providing rotating blades on the cavity/bowl of the reciprocating piston head. By putting a simple link mechanism, the oscillatory motion of connecting rod will rotate the blade by an angle of 60°. Findings The investigations are carried out with and without swirl piston at 17.5 compression ratio and 200 bar injection pressure by varying injection timings. Originality/value Finally, the result shows that by using the modified piston, nearly 3 per cent of efficiency increased and 31 per cent of NOx emissions are reduced compared to that of a normal piston with 80 per cent load at standard injection timing.

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