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The lack of integrity of the piston machine combustion chamber manifests itself in leakages of the working fluid between the piston and the cylinder liner, at valves mounted in the cylinder head and between the head and the liner. An untight combustion chamber leads to decreased power output or efficiency of the engine, while leaks of a fluid may cause damage to many components of the chamber. The actual value of working chamber leak is a desired and essential piece of information for planning operations of a given machine.

This research paper describes causes and mechanisms of leakage from the working chamber of internal combustion engines. Besides, the paper outlines presently used methods and means of leak identification and states that their further development and improvements are needed. New methods and their applicability are presented.

The methods of leak identification have been divided into diagnostic and non-working machine leak identification methods. The need has been justified for the identification of leakage from the combustion chamber of a non-working machine and for using the leakage measure as the value of the cross-sectional area of the equivalent leak, defined as the sum of cross-section areas of all leaking paths. The analysis of possible developments of tightness assessment methods referring to the combustion chamber of a non-working machine consisted in modelling subsequent combustion chamber leaks as gas-filled tank leak, leak from another element of gas-filled tank and as a regulator of gas flow through a nozzle.

A measurement system was built allowing the measurement of pressure drop in a tank with the connected engine combustion chamber, which indicated the usefulness of the system for leakage measurement in units as defined in applicable standards. A pneumatic sensor was built for measuring the cross-sectional area of the equivalent leak of the combustion chamber connected to the sensor where the chamber functioned as a regulator of gas flow through the sensor nozzle. It has been shown that the sensor can be calibrated by means of reference leaks implemented as nozzles of specific diameters and lengths. The schematic diagram of a system for measuring the combustion chamber leakage and a diagram of a sensor for measuring the cross-sectional area of the equivalent leak of the combustion chamber leakage are presented. The results are given of tightness tests of a small one-cylinder combustion engine conducted by means of the set up measurement system and a pre-prototype pneumatic sensor. The two solutions proved to be practically useful.

The purpose is to develop and apply a systematic simulation approach for dynamic analysis in order to study a two combustion chambers liquid propellant engine.

The logic of the simulation method and the software is based on following the liquids. The implicit nonlinear algebraic equations are solved using a number of nested Newton‐Raphson loops, and the nonlinear and time varying differential equations are solved using a first‐order Euler technique.

It is found that the developed simulation code predicts the steady‐state values with errors under 5 percent, and this code has the capability to be used in studying the effect of various elements and subsystems parameters on the forecasting the performance and operation of the engine system.

At present, the research is limited to a specific liquid propellant engine. Development of a general purpose software package for simulation of liquid propellant engines, based on the developed simulation algorithm, is subject of future research.

The major outcome of this research is that verifies liquid engine simulation code may be used as a suitable tool to optimize the engine.

This is the first paper in the area of a two combustion chambers engine simulation and dynamic analysis that is based on the application of an existing simulation algorithm.

In contrast with previously known methods of calculating the volume of rocket combustion chambers which are concerned with a ‘characteristic length’ to be determined experimentally for each fuel and for each injection system, it will be shown that there is available: (a) a generally valid qualitative theoretical relationship between the combustion chamber volume VC and any desired combustion pressure, mass flow, fuel and combustion chamber shape. (b) a generally valid relationship, for practical design purposes, between the combustion chamber volume VC and any desired combustion pressure, mass flow, fuel and combustion chamber shape. Further, the theoretical results will be compared, by means of examples, with combustion chambers which have been tested in practice. Moreover, the important fact will be indicated that the formula proposed in this article must, in principle, also be applicable to the calculation of the volume of the gas turbine combustion chamber.

The purpose of this computational fluid dynamics (CFD) study is to give insight about the influence of the piston bowl geometry and the fuel ignition features on the resonance of direct injection diesel engines combustion chambers in order to provide support to the experimental findings on combustion noise.

The resonance due to the burned gases oscillations in a diesel combustion chamber is caused by the sudden rise in pressure due to the initial ignition of the air‐fuel mixture, and leads to the resonance noise. In the CFD study presented here the excitation source is represented by imposing locally in a small area (excitation zone) the pressure and temperature gradients of the start of combustion. The CFD approach is first validated against the acoustic modal theory. A parametric study representing different ignition conditions is then performed with a real bowl geometry.

The solutions obtained are analysed in terms of the energy of resonance (ER) and the response in the frequency domain. It was found that the response in frequency only varies with the diameter of the bowl, while the ER varies significantly in function of the injection conditions.

These first conclusions need to be verified on the one hand by taking into account the piston motion, and, on the other hand, by modelling in a more realistic way the combustion excitation.

This CFD study has brought some insight into the flow phenomena that affect the resonance modes of a combustion chamber.

This CFD study uses a novel methodology to model the effect of the combustion excitation on the resonance modes of a combustion chamber.

The paper is mainly concerned with how the gas‐turbine designer can choose the best design of liquid or gaseous fuel combustion chamber for his purpose. In the method proposed, combustion chamber test data are expressed in a way which gives the most general information about the design, by introducing dimensionless performance criteria. These criteria are then plotted in ways which enable the various chamber designs to be compared. The treatment deals implicitly with the conditions which satisfactory model tests must fulfil. An idealized model of a gas‐turbine combustion chamber is introduced in the light of which the effects of changes in overall fuel/air ratio can be explained more satisfactorily than when conditions in the flame‐tube are supposed homogeneous.

THIS paper will be confined to oil fuel, which has been used so far to a predominating extent in the gas turbine. It is possible that some of the general matters touched upon will be applicable to gaseous or solid fuels, such as aero‐dynamic patterns within a combustion zone, wall cooling and effects of ash.

Ideal and practical performance of ram‐jet units in steady flight in the stratosphere at Mach numbers from 1·5 to 4 is examined. The effects of combustion, temperature, altitude, intake and exhaust nozzle design are considered.

THE rocket motor is a form of jet propulsion which is characterized by independence of the external atmosphere for combustion, relative independence of altitude and flight velocity upon thrust, small frontal area for high thrusts, simple construction and low weight, and high rate of fuel consumption. Its use was greatly developed during the war years and many applications are now familiar to all. Most of the work on rocket missiles, such as the anti‐aircraft barrages, fighter armament, etc., was performed with solid fuel rockets, but liquid fuels were developed by the Germans for the well‐known V.2, for the Me. 163 aircraft, the Henschel glide bomb and various other applications. They concentrated a great deal of effort on this work and considerable technical progress had been made with different systems. Three main systems emerged and these were distinguished by the oxygen bearing fluids they used. The fluids were:

The reaction dynamics of combustible clouds at high temperatures and pressures are a common form of energy output in aerospace and explosion accidents. The cloud explosion process is often affected by the external initial conditions. This study aims to numerically study the effects of airflow velocity, initial temperature and fuel concentration on the explosion behavior of isopropyl nitrate/air mixture in a semiconstrained combustor.

The discrete-phase model was adopted to consider the interaction between the gas-phase and droplet particles. A wave model was applied to the droplet breakup. A finite rate/eddy dissipation model was used to simulate the explosion process of the fuel cloud.

The peak pressure and temperature growth rate both decrease with the increasing initial temperature (1,000–2,200 K) of the combustor at a lower airflow velocity. The peak pressure increases with the increase of airflow velocity (50–100 m/s), whereas the peak temperature is not sensitive to the initial high temperature. The peak pressure of the two-phase explosion decreases with concentration (200–1,500 g/m³), whereas the peak temperature first increases and then decreases as the concentration increases.

Chain explosion reactions often occur under high-temperature, high-pressure and turbulent conditions. This study aims to provide prevention and data support for a gas–liquid two-phase explosion.

Sustained turbulence is realized by continuously injecting air and liquid fuel into a semiconfined high-temperature and high-pressure combustor to obtain the reaction dynamic parameters of a two-phase explosion.

The purpose of this paper is to investigate the performance of coke oven gas (COG)-combined cooling, heating and power (CCHP) system and to mainly focus on studying the influence of the environmental conditions, operating conditions and gas conditions on the performance of the system and on quantifying the distribution of useful energy loss and the saving potential of the integrated system changing with different parameters.

The working process of COG-CCHP was simulated through the establishment of system flow and thermal analysis mathematical model. Using exergy analysis method, the COG-CCHP system’s energy consumption status and the performance changing rules were analyzed.

The results showed that the combustion chamber has the largest exergy loss among the thermal equipments. Reducing the environmental temperature and pressure can improve the entire system’s reasonable degree of energy. Higher temperature and pressure improved the system’s perfection degree of energy use. Relatively high level of hydrogen and low content of water in COG and an optimal range of CH₄ volume fraction between 35 per cent and 46 per cent are required to ensure high exergy efficiency of this integration system.

This paper proposed a CCHP system with the utilization of coke oven gas (COG) and quantified the distribution of useful energy loss and the saving potential of the integrated system under different environmental, operating and gas conditions. The weak links of energy consumption within the system were analyzed, and the characteristics of COG in this way of using were illustrated. This study can provide certain guiding basis for further research and development of the CCHP system performance.