injection nozzle
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Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8555
Author(s):  
Taejung Kim ◽  
Yunchan Shin ◽  
Jungsoo Park ◽  
Honghyun Cho

In the present study, a nozzle was used to improve the flow performance of an intake manifold, and its effects on the automobile engine output and the exhaust gas were experimentally studied. It was found that the engine output of a vehicle with a mileage of 30,000 km increased by 4.7% and 6.5% when nozzles with diameters of 5 and 2.5 mm were used. In addition, the engine output of a vehicle with a mileage of 180,000 km increased by 3.3% and 13.3% when nozzles with diameters of 5 and 2.5 mm were used compared to those of the same vehicle when no nozzle was used. Thus, using a nozzle for the inflow of outside air created a uniform combustion environment to improve the engine output and reduce harmful exhaust gases, such as hydrocarbon, carbon monoxide, and nitrogen oxides, by generating vortexes inside the intake manifold and increasing the degree of mixing. Furthermore, the smaller nozzle with a diameter of 2.5 mm had greater effects.


2021 ◽  
Vol 13 (2-3) ◽  
pp. 113-123
Author(s):  
Wen Hua ◽  
Zhang Xin-yu ◽  
Jiang Yu-long ◽  
Zhao Ling-yao

The fuel flow pattern in the fuel injection nozzle of diesel engine is a complex and changeable phenomenon, which is easily affected by various factors, bringing the differences of flow patterns between multiple injection cycles. To solve the above problem, a visual experimental platform of fuel injection nozzle was built, in which the 100 injection cycles of diesel engine on the same working condition were photographed via shadowgraphy to study the difference in fuel flow pattern in the nozzle by ensemble average processing method. The cyclic variation rate K of fuel flow pattern is defined. Results demonstrate that the fuel flow pattern tends to be the same in multiple fuel injection cycles, but there is a strong randomness at the starting of injection and after ending of injection; the K can be reduced by decreasing the injection pressure and the inclination angle of orifice, so that the fuel flow pattern in the nozzle tends to be consistent.


2021 ◽  
Author(s):  
Lawrence D. Berg ◽  
Soroor Karimi ◽  
Siamack A. Shirazi

Abstract Coal use for generation of electricity is used extensively world-wide accounting for 40% of total power generation. Even with reductions in use over the last 10 years, coal still accounts for 20% of total electrical generation in the United States. An often-overlooked aspect of Pulverized Coal (PC) combustion is the erosion and abrasion of the coal injection nozzles. Currently there are over 300 active PC boilers in the US and over 1000 worldwide, with each boiler having 20–40 high alloy cast injectors. Due to the high velocity of PC injection and associated elevated rates of metal loss, these nozzles require constant replacement. Replacement and costs associated with loss of revenue, required scaffolding and casting can be a significant part of Operation and Maintenance (O&M) of a PC boiler. In addition to the constant requirement for thousands of replacement injection nozzles every year, combustion performance, NOx reduction, carbon conversion and general boiler efficiency will be impacted by hardware that is out of specification, if not replaced in a “timely” manner. Significant research in the 1980’s [1] provided some insight into the loss-of-metal process during PC injection, but limitations of existing hardware and software prevented more than an empirical methodology to be developed. In parallel with the literature work and research specifically for PC coal erosion rates, generalized efforts were employed and reported [6–9]. Meng [4] summarized model development for solid particles transported by a liquid or gas as highly empirical with little commonality between the models developed by the various researchers. Meng also made specific recommendations for less empiricism in model development methodology. Although there are several state-of-the-art empirical models [6, 8 & 9] more recently, semi-mechanistic models have been developed to predict solid particle erosion (e.g. Arabnejad et al., [17]) and have been successfully applied to sand erosion and abrasion in pipelines. In the current study, this method is being applied to PC injection nozzles coupled to detailed computational fluid dynamics (CFD) simulations. The intent is to quantify nozzle material loss rates, due to impacting coal particles, as a function of geometry, local velocities, and coal properties. The method used is utilizing CFD to model flow of particles and their impingement velocity with the PC nozzles. Then erosion models that are a function of impingement speed, angle, frequency and materials properties to examine erosion rates. The insight gained from the modeling will allow improved nozzle design, increased duty life, more cost-effective supply, and elevated injection velocity. In particular, low NOx coal combustion can be critically dependent on utilization of elevated injection velocities, which previous empirical models discourage. This paper reports on the application of the erosion equations and methods developed at the Erosion/Corrosion Research Center of The University of Tulsa for predicting solid particle erosion of a PC injection nozzle that shows details of erosion patterns and parameters that are responsible for elevated erosion tendencies in the field. RJM-International is familiar with the nozzle from various applications that are associated with Low NOx operation. The advantages of utilizing semi-mechanistic erosion equations and models coupled with CFD simulations as compared to previous empirical methods are discussed. Shortcomings of applying the existing coal erosion model is also reported along with “next steps” required to successfully apply the method to PC injection nozzle designs for much higher combustion efficiencies than existing ones.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4359
Author(s):  
Vladislav Emelyanov ◽  
Mikhail Yakovchuk ◽  
Konstantin Volkov

The optimal design of the thrust vector control system of solid rocket motors (SRMs) is discussed. The injection of a supersonic underexpanded gas jet into the diverging part of the rocket engine nozzle is considered, and multiparameter optimization of the geometric shape of the injection nozzle and the parameters of jet injection into a supersonic flow is developed. The turbulent flow of viscous compressible gas in the main nozzle and injection system is simulated with the Reynolds-averaged Navier–Stokes (RANS) equations and shear stress transport (SST) turbulence model. An optimization procedure with the automatic generation of a block-structured mesh and conjugate gradient method is applied to find the optimal parameters of the problem of interest. Optimization parameters include the pressure ratio of the injected jet, the angle of inclination of the injection nozzle to the axis of the main nozzle, the distance of the injection nozzle from the throat of the main nozzle and the shape of the outlet section of the injection nozzle. The location of injection nozzle varies from 0.1 to 0.9 with respect to the length of the supersonic part of the nozzle; the angle of injection varies from 30 to 160 degrees; and the shape of the outlet section of the injection nozzle is an ellipse with an aspect ratio that varies from 0.1 to 1. The computed fluid flow in the combustion chamber is compared with experimental and computational results. The dependence of the thrust as a function of the injection parameters is obtained, and conclusions are made about the effects of the input parameters of the problem on the thrust coefficient.


2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Ikhtedar Husain Rizvi ◽  
Rajesh Gupta

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.


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