Estimation of the influence of air bypass along the length of the combustion chamber on efficiency of operating process in a model rig with energy-intensive condensed materials

2021 ◽  
pp. 17-22
Author(s):  
E.V. Surikov ◽  
M.S. Sharov ◽  
P.A. Kolomentsev ◽  
O.M. Alekseeva
2018 ◽  
Vol 224 ◽  
pp. 02057
Author(s):  
Anas S. Gishvarov ◽  
Julien Celestin Raherinjatovo

The article presents a method of parametric diagnostics of the condition of a dual-flow turbojet engine (DFTE). The method is based on the identification (determination) of the condition of the DFTE components (the compressor, combustion chamber, turbine) with application of a mathematical model of the operating process which is presented as an artificial neural network (ANN) model. This model describes the relation between the monitored parameters of the DFTE (the air temperatures (Tlpc*, Thpc*) beyond the low pressure compressor (LPC) and the high pressure compressor (HPC), the pressure beyond the LPC (Plpc), the fuel consumption rate (Gf), the gas temperatures (Thpt*, Tlpt*) beyond the high pressure turbine (HPT) and the low pressure turbine (LPT)) and the parameters of the condition of its components (the efficiencies of the LPC and the HPC (ηlpc*, ηhpc*), the stagnation pressure recovery factor in the combustion chamber (σcc), the efficiencies of the HPT and the LPT (ηhpt*, ηlpt*)). The parameters of the condition of the engine components (ηlpc*, ηhpc*, σcc, ηhpt*, ηlpt*) are the similarity criteria (integral criteria) which enable to identify the condition of the DFTE components to a high degree of reliability. Such analysis enables to detect defects at an early stage, even if the values of the monitored parameters (Тlpc*, Тhpc*, Plpc, Gf, Тhpt*, Тlpt*) are within the permissible limits. We provide the sequence for development of the ANN model and the results of its performance study during the parametric diagnostics of the condition of the DFTE.


2017 ◽  
Vol 17 ◽  
pp. 245-252
Author(s):  
V. V. Somov

In carrying out an investigation into the explosion, among others, the investigative version of the use of a single-use reactive grenade launcher is being considered. The most common for criminal explosions are applied grenade launchers RPG-18, RPG-22, RPG-26. Their use is due to a number of such properties as small size and weight, which makes it possible to transfer them covertly, the range of the shot significantly exceeding the range of the hand grenade throw, the high detonating effect of the rocket grenade explosion. The single-use rocket launchers are generally of the same design. Their differences are in the features of the components construction and dimensional characteristics, which are given in the article. On the basis of expert practice, details ofgrenade launchers that remain at the site of the explosion and have the least damage are determined. These details are the objects of investigation of the explosion technical expertise. These objects include launchers of grenade launchers and rocket parts ofjet grenades. The design features of the launchers, their dimensional characteristics and marking symbols make it possible to determine their belonging to a specific type of jet grenade launchers. Missile parts of jet grenades differ in the form of the combustion chamber of the jet engine, nozzle, in the size ofthe outlet section of the nozzle, in the form and size of the stabilizerfeathers. To determine the belonging of the rocket part of the grenade to a specific type ofjet grenade launcher, it’s necessary to establish a set of structural features and dimensional characteristics. At considerable damage of the combustion chamber of the jet engine, as a rule, the nozzle block remains intact that allows to define diameter of critical section of a nozzle, and on it to establish type of the used single-use grenade launcher.


Author(s):  
Serhii Kovalov

The expediency of using vehicles of liquefied petroleum gas as a motor fuel, as com-pared with traditional liquid motor fuels, in particular with diesel fuel, is shown. The advantages of converting diesel engines into gas ICEs with forced ignition with respect to conversion into gas diesel engines are substantiated. The analysis of methods for reducing the compression ratio in diesel engines when converting them into gas ICEs with forced ignition has been carried out. It is shown that for converting diesel engines into gas ICEs with forced ignition, it is advisable to use the Otto thermo-dynamic cycle with a decrease in the geometric degree of compression. The choice is grounded and an open combustion chamber in the form of an inverted axisymmetric “truncated cone” is developed. The proposed shape of the combustion chamber of a gas internal combustion engine for operation in the LPG reduces the geometric compression ratio of D-120 and D-144 diesel engines with an unseparated spherical combustion chamber, which reduces the geometric compression ratio from ε = 16,5 to ε = 9,4. The developed form of the combustion chamber allows the new diesel pistons or diesel pistons which are in operation to be in operation to be refined, instead of making special new gas pistons and to reduce the geometric compression ratio of diesel engines only by increasing the combustion chamber volume in the piston. This method of reducing the geometric degree of compression using conventional lathes is the most technologically advanced and cheap, as well as the least time consuming. Keywords: self-propelled chassis SSh-2540, wheeled tractors, diesel engines D-120 and D-144, gas engine with forced ignition, liquefied petroleum gas (LPG), compression ratio of the internal com-bustion engine, vehicles operating in the LPG.


Author(s):  
A. P. Shaikin ◽  
I. R. Galiev

The article analyzes the influence of chemical composition of hythane (a mixture of natural gas with hydrogen) on pressure in an engine combustion chamber. A review of the literature has showed the relevance of using hythane in transport energy industry, and also revealed a number of scientific papers devoted to studying the effect of hythane on environmental and traction-dynamic characteristics of the engine. We have studied a single-cylinder spark-ignited internal combustion engine. In the experiments, the varying factors are: engine speed (600 and 900 min-1), excess air ratio and hydrogen concentration in natural gas which are 29, 47 and 58% (volume).The article shows that at idling engine speed maximum pressure in combustion chamber depends on excess air ratio and proportion hydrogen in the air-fuel mixture – the poorer air-fuel mixture and greater addition of hydrogen is, the more intense pressure increases. The positive effect of hydrogen on pressure is explained by the fact that addition of hydrogen contributes to increase in heat of combustion fuel and rate propagation of the flame. As a result, during combustion, more heat is released, and the fuel itself burns in a smaller volume. Thus, the addition of hydrogen can ensure stable combustion of a lean air-fuel mixture without loss of engine power. Moreover, the article shows that, despite the change in engine speed, addition of hydrogen, excess air ratio, type of fuel (natural gas and gasoline), there is a power-law dependence of the maximum pressure in engine cylinder on combustion chamber volume. Processing and analysis of the results of the foreign and domestic researchers have showed that patterns we discovered are applicable to engines of different designs, operating at different speeds and using different hydrocarbon fuels. The results research presented allow us to reduce the time and material costs when creating new power plants using hythane and meeting modern requirements for power, economy and toxicity.


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