scholarly journals Improvement of mixing processes in diesel engines

2021 ◽  
Vol 3 (1(59)) ◽  
pp. 16-18
Author(s):  
Ludmila Knaub

The object of research is gas-dynamic vortex processes in heterogeneous polydisperse flows. One of the most problematic issues in engine building is the completeness of combustion and the rate of fuel burnout in the given coordinates on the allotted hourly interval in the combustion chamber. These indicators, in turn, determine stringent requirements for used fuels in terms of thermophysical parameters that affect sawing, evaporation and mixing with an oxidizer. In the course of the study, methods of mathematical modeling were used based on the theory of similarity. Methods have been developed for preparing a combustible mixture for detonation-free combustion of a cheap alternative fuel. A method for assessing the quality of spraying low cetane fuel is proposed. A mathematical model is obtained for calculating the change in the parameters of the quality of atomization and the differential characteristics of fuel injection. This is necessary for theoretical studies of gas-dynamic processes in additional power systems for diesel engines in an unsteady three-dimensional flow with variable parameters of a polydisperse flow of a combustible mixture. It has been proven that with a decrease in the camshaft rotational speed, the injection speed will be insufficient to achieve the required spray quality due to a decrease in the speed. This made it possible to redesign the additional system using a separate dual fuel supply. Research samples of an additional power supply system for the ЯМЗ–24 ОН diesel engine (Yaroslavl Motor Plant, Russia) have been developed. Comparative tests of the engine operation on stable gas condensate with the main fuel equipment and an additional system have been carried out. Oscillograms of the tests were obtained and analyzed. The research results provided the basis for the use of low cetane cheap gas condensate in diesel engines. This will improve the economic, power and environmental performance of the engines. Compared to standard cetane fuels, the price of fuel will decrease by 40 %, engine power will increase by 20 %, and the environmental performance of exhaust gases will decrease by 10–30 %.

2015 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
D.N. Basavarajappa ◽  
N. R. Banapurmath ◽  
S.V. Khandal ◽  
G. Manavendra

For economic and social development of any country energy is one of the most essential requirements. Continuously increasing price of crude petroleum fuels in the present days coupled with alarming emissions and stringent emission regulations has led to growing attention towards use of alternative fuels like vegetable oils, alcoholic and gaseous fuels for diesel engine applications. Use of such fuels can ease the burden on the economy by curtailing the fuel imports. Diesel engines are highly efficient and the main problems associated with them is their high smoke and NOx emissions.  Hence there is an urgent need to promote the use of alternative fuels in place of high speed diesel (HSD) as substitute. India has a large agriculture base that can be used as a feed stock to obtain newer fuel which is renewable and sustainable. Accordingly Uppage oil methyl ester (UOME) biodiesel was selected as an alternative fuel. Use of biodiesels in diesel engines fitted with mechanical fuel injection systems has limitation on the injector opening pressure (300 bar). CRDI system can overcome this drawback by injecting fuel at very high pressures (1500-2500 bar) and is most suitable for biodiesel fuels which are high viscous. This paper presents the performance and emission characteristics of a CRDI diesel engine fuelled with UOME biodiesel at different injection timings and injection pressures. From the experimental evidence it was revealed that UOME biodiesel yielded overall better performance with reduced emissions at retarded injection timing of -10° BTDC in CRDI mode of engine operation.


2021 ◽  
Vol 2131 (2) ◽  
pp. 022074
Author(s):  
S Andriushchenko ◽  
S Titov ◽  
G Yur

Abstract Currently, environmental specifications of marine diesel engines become more stringent. There are two well-known and popular ways to improve engine environmental performance: the internal method is based on operation process improvement, as well as on the use of various fuel additives or air supply to the diesel cylinder. Another method is external (gas purification using catalysts and filters). The article considers one of these possible ways of reducing nitrogen oxides in marine diesel engines by using a water agent in fuel with various water phase dispersion degrees. The high-speed characteristics of the ship engine operation under various modes using “L” brand diesel fuel and emulsions are given. Studies have shown that when converting diesel from pure fuel to a microheterogenous emulsion (water inclusions’ diameter 5-10 microns), the concentration of NOx decreased by 1.4 times, fuel consumption increased by (4-5) g/(kWh), with an increase in the maximum combustion pressure by 0.7 MPa. The tests have confirmed the effectiveness of using a microheterogenous emulsion to reduce nitrogen oxide emissions.


Author(s):  
Moch Miftahul Arifin ◽  
Nasrul Ilminnafik ◽  
Muh. Nurkoyim Kustanto ◽  
Agus Triono

Technological developments in diesel engines require improvements to the fuel injection system to meet the criteria for economical, high-power and efficient combustion and meet environmental regulatory standards. One method that has a lot of interest is changing the characteristics of the fuel, with the aim of producing optimal combustion. Spray characteristics have a big role in determining the quality of combustion in diesel engines. A good spray can improve the quality of fuel atomization and the homogeneity of the air-fuel mixture in the combustion chamber so that it can produce good engine performance and low emissions. This study aims to determine the effect of a diesel-biodiesel (Calophyllum inophyllum)-gasoline blendandfuel heating on the spray characteristics. The research was conducted with variations in composition (B0, B100, B30, B30G5 and B30G10) and fuel heating (40, 60, 80, and 100 °C). Fuel injected atapressure of 17 MPa in to a pressure chamber of 3 bar. The spray formed was recorded with a high-speed camera of 480 fps (resolution 224x168 pixel). In B100 biodiesel, the highest viscosity and density cause high spray tip penetration, small spray angle, and high spray velocity. The addition of diesel oil, gasoline, and heating fuel reduces the viscosity and density so that the spray tip penetration decreases, the spray angle increases and the velocity of spray decreases.


Author(s):  
S Tonini ◽  
M Gavaises ◽  
C Arcoumanis ◽  
A Theodorakakos ◽  
S Kometani

A multi-component fuel vaporization model has been developed and implemented into an in-house multi-phase computational fluid dynamics flow solver simulating the flow, spray, and air-fuel mixing processes taking place in gasoline direct injection (GDI) engines. Multi-component fuel properties are modelled assuming a specified composition of pure hydrocarbons. High-pressure and -temperature effects, as well as gas solubility and compressibility, are considered. Remote droplet vaporization is initially investigated in order to quantify and validate the most appropriate vaporization model for conditions relevant to those realized with GDI engines. Phenomena related to the fuel injection system and pressure-swirl atomizer flow as well as the subsequent spray development are considered using an one-dimensional fuel injection equipment model predicting the wave dynamics inside the injection system, a Eulerian volume of fluid-based two-phase flow model simulating the liquid film formation process inside the injection hole of the swirl atomizer and a Lagrangian spray model simulating the subsequent spray development, respectively. The computational results are validated against experimental data obtained in an optical engine and include laser Doppler velocimetry measurements of the charge air motion in the absence of spray injection and charge coupled device images of the fuel spray injected during the induction stroke. The results confirm that fuel composition affects the overall fuel spray vaporization rate, but not significantly relative to other flow and heat transfer processes taking place during the engine operation.


2021 ◽  
Vol 61 (3) ◽  
pp. 435-447
Author(s):  
Dmytro S. Minchev ◽  
Roman A. Varbanets ◽  
Nadiya I. Alexandrovskaya ◽  
Ludmila V. Pisintsaly

The ongoing monitoring of marine diesel engines helps to detect the deviations of its parameters early and prevent major failures. But the experimental diagnostics data are generally limited, so frequently, it isn’t possible to get all the necessary information to make a clear decision. The mathematical simulation could be used to clarify the experimental data and to provide a deeper understanding of engine conditions. In this paper, the MAN 6L80MCE marine diesel engine of “Father S” bulk carrier diagnostics issues are considered. The diagnostics data were collected with DEPAS Handy equipment and present the information about indicated processes by every engine cylinder. The on-line resource Blitz-PRO was used for the simulation of the engine operation and helped to prove that the variation in exhaust valve’s closing timing is responsible for the observed compression pressure difference, while the irregularity in fuel injection causes the considerable difference in the maximum pressure.


2018 ◽  
Author(s):  
Ibukun Makinde

Gas condensates are liquid mixtures of high-boiling hydrocarbons of various structures, separated from natural gases during their production at gas condensate fields. When transporting gas through pipelines, the following gas quality conditions should be met:i.During transportation, gases should not cause corrosion of pipelines, fittings, instruments, etc.ii.The quality of the gas must ensure its transportation in a single-phase state i.e., liquid hydrocarbons, gas condensates and hydrates should not form in the pipelines.In order for gas condensates to meet the above-mentioned quality conditions during storage or transportation, they must be stabilized. Gas condensate stabilization is the process of “boiling off” light hydrocarbons from the condensate that would otherwise increase the vapor pressure when conditions are fluctuating.


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