Pulse Jet Engines Research Articles

On the Effect of Internal Aerodynamics and Fuel Combustion Rate on the Thrust of a Valveless Pulsejet Engine

On the Effect of Internal Aerodynamics and Fuel Combustion Rate on the Thrust of a Valveless Pulsejet Engine

Sources of Self-Oscillations in an Ejector Pulsejet Engine

Sources of Self-Oscillations in an Ejector Pulsejet Engine

Current Status of Jet Engines and Their future

Jet engines have important application value and status in the aerospace field, which directly affects the development of aircraft and spacecraft. This year, jet engines have gradually become the focus and hotspot of scholars at home and abroad. Through the method of literature comparison and analysis, this paper focuses on analysing two common jet engines, namely turbofan engine and pulse jet engine, and makes a detailed analysis and comparison of their working principles and applications; for the future development of parts, three-dimensional (3D) printing technology as an example, the use of different kinds of 3D printing, electron beam melting and selective laser melting to print jet engine parts and how to reduce errors is studied, and various techniques for improving high temperature parts are analysed., and looked forward to the future development trend of jet engines and put forward their own views. The research work in this paper will promote the development of jet engine and provide reference for engineers and technicians.

Interaction Behavior of Pulsejet Engines

Valveless pulsejet engines are analyzed as electric circuits in which the main engine components (inlet, combustion chamber, and tailpipe) are assigned impedance values and represented using a system of linear equations. The solution to these equations yields Bode plots for the engines that can be used to predict operating frequency as well as the effects of individual component dimensions on overall engine behavior. This method of analysis is found to predict engine operating frequencies to within 7% of experimentally measured values. The analysis is extended to include systems of multiple engines and again verified by comparison to experiment. It is shown that multiple engines can be locked in phase or in antiphase predictably by selecting the proper interconnection method. The latter has important implications for noise reduction and for propulsion applications involving arrays of pulsejets.

A new approach to the phenomenon of pulsed combustion

Despite the multiple use and testing of pulse combustion devices, there is a great deal ofuncertainty about the very processes taking place in the pulsating combustion chamber. Theresearch program carried out by the authors of this study focused on the parameters influencing periodic combustion in a valveless pulsating combustion chamber (pulse jet engine). The obtained results surprisingly showed that it is possible to greatly influence theoperation of the pulsating combustion chamber, which does not necessarily have tofunction as an acoustic device. It has been found that the appropriate fuel supply allows tochange the operating frequency, the amplitude of the pressure in the combustion chamber as well as the amplitude of the thrust.

Laser engine based on the ablative-reactive effect in films

The operation principle and design of a solid-fuel laser pulse jet engine are proposed. An experimental confirmation of the proposed operation principle of the laser engine has been obtained. Keywords: Ablation, laser engine.

Лазерный двигатель на основе абляционно-реактивного эффекта в пленках

The operation principle and design of a solid-fuel laser pulse jet engine are proposed. An experimental confirmation of the proposed operation principle of the laser engine has been obtained.

Inner Separation Area Precession as a Source for Initiating the Detonation or Quasi-Detonation Combustion in an Ejector Pulsejet Engine

Inner Separation Area Precession as a Source for Initiating the Detonation or Quasi-Detonation Combustion in an Ejector Pulsejet Engine

Numerical Comparison between Two Tailpipe Shapes of Valved Pulsejet Engine

In this article, the valved pulsejet engine has been numerically investigated using Ansys/fluent (CFD) program. The designed model has a 1400 cm length and 17 cm combustion chamber diameter connected with one of two different shapes of exhaust pipe that has the same length (45 cm). The first shape has a 12 cm constant diameter abbreviated by the constant D; the second has a differential diameter in which the near and far ends are having 12 cm and 15 cm, respectively, and also denoted by different D. The conclusion was the maximum velocity is the same value (46 m/s) in the two cases but centered at the beginning of different D case. In the constant D case, the velocity was distributed in the last 45cm of the exhaust pipe. The maximum pressure generated in the combustion chamber in the constant D case is twice the value compared to the second case. In the case of different D, the pressure curve has a rather strange behavior. The temperature distribution exhibits the same behavior in both cases, but the engine has a different diameter tailpipe generate temperature more significant than the second case by 10%.

Possibilities of Using Bioethanol as an Alternative Fuel in the Conditions of Jet Engines

In today’s world, reducing the ecological impact of transport on the environment plays a key role in air transport, as a major polluter of the environment. The rate of use of solid fuels is a current parameter in the process of using renewable energy sources as well as reducing emissions from combustion engines. The article focuses on the use of bioethanol as an alternative fuel in aircraft engines, specifically in pulsejet engines. The partial goal of the manuscript was to create a functional measuring bench, which was equipped with pulsejet engine, sensors equipment and control unit. The manuscript mentions the use of a pulsed Lockwood-Hiller engine type, which was operated with three types of fuels (Gas N-95, Diesel and JET-A1 Kerosene) compared to bioethanol. The results of the experiments demonstrated the possibilities of using alternative fuels and their specific properties compared to conventional fuels and the possibility of implementation into real operation. It was the unique combustion processes of pulse engines that enabled the study at the border of the continuous and cyclic combustion process and the usability of bioethanol for aircraft engines. With regard to fuel use, it is assumed that alternative fuels will be a way to reduce the impact of aviation emissions and, in particular, to make more efficient use of renewable fuel sources.

Dynamic Features of Internal and External Flowfields of Pulsejet Engines

The spectral proper orthogonal decomposition method, which extracts spatially and temporally coherent modes in stationary flowfields, is used in the current paper to analyze high-speed broadband chemiluminescence and shadowgraph videos taken the internal and external flowfields, respectively, of multiple pulsejet engine geometries. By comparing the modes of highest energies across geometric variations of tailpipe length as well as the presence or absence of a nozzle flare at the exit, we showcase features of notable, but hidden, combustion and fluid dynamic interest that help sustain the cyclic and unsteady operation. Two different vortical systems develop internally. The primary is a strong toroidal vortex caused by rapid reed valves’ closure at the headwall. The second is a shedding vortex, which is seen to tear itself apart from the primary vortex due to the inertia of the incoming fresh reactants. Based on the engine geometry, one of the two is shown to be a considerably stronger dynamic flow feature. In the exhaust, the presence of a diverging nozzle flare causes two distinct starting vortices. When the exhaust is just a straight tube, only one starting vortex is formed. We link this to the fluidic piston effect accompanying the Helmholtz resonance in these devices. Point-source pressure sensors are used to complement the information attained from the video analyses.

Modelling & numerical exploration of pulsejet engine using eddy dissipation combustion model

The pulsejet engine is relatively simple engine used in missiles but the combustion modeling of pulsejet engine is relatively complex through numerical analysis procedure. The current research investigates the application of eddy dissipation model in analyzing the combustion and thus thrust generation. Three different fuel inlet designs of pulsejet engine are considered for analysis i.e. single inlet, three inlet and five inlets. The Jet Air combustion is modeled under pseudo static steady state conditions. The CFD analysis is conducted using ANSYS CFX analysis package and CAD model is developed in PTC Creo design software. The static enthalpy, thrust and velocity are determined for all the three designs. The research findings have shown that the fuel to air ratio has significant effect on thrust generation from pulsejet engine. The turbulence kinetic energy is highest near the walls and near nozzle which reduces as we move away from it.

Experimental and Computational Design and Testing of a Valve Less Pulsejet Engine for the Application of Micro Air Vehicle

Experimental and Computational Design and Testing of a Valve Less Pulsejet Engine for the Application of Micro Air Vehicle

Revisiting the Argus pulsejet engine of V-1 buzz bombs: An experimental investigation of the first mass-produced pressure gain combustion device

Recent years have witnessed heightened focus on the operability and feasibility of various pressure gain combustion devices due to their attractive promise of increased thermodynamic efficiency. One such widely-researched pressure gain combustor is the pulsejet. The current paper details an experimental investigation performed on the most well-known pulsejet: the Argus As 014 pulsejet engines that were used to power the infamous V-1 “buzz” bombs during World War II. Incidentally, these engines also appear to be the most mass produced pressure gain combustors to date – more than 10,000 were launched at targets and many more manufactured. The engine tested here contains the actual outer casing made during the war, while the inner motor containing the shutter valves, air and fuel injection assemblies are dimensionally- and functionally-matching replicas made more recently. The exhaust plume behavior, far-field acoustic signature, skin and exit gas temperature, timing from valve opening to ignition and exhaust are gathered. The formation number of the ejected starting vortex is seen to be 2.5 and 3 for the conditions tested. The acoustic signature exhibits a peculiar directivity not seen in other unsteady devices, while producing up to 128 dB. The engine attains thermal steady-state within 15 s. However, the highest temperature is measured at the exhaust after a considerable distance of more than one meter. Finally, using the timing information and the other variables, it is noted that the Argus engine appears to behave like a Helmholtz resonator and not a quarter-wave as previously contended.

Geometrical modeling of the process of weaving a wire cloth in weightlessness using the inertial unfolding of a dual pendulum

We proposed a geometrical model for weaving a wire cloth using the oscillations of a system of two-link pendulums within an abstract plane and under conditions of weightlessness. It is expected to initiate oscillations through the application of pulses to each of the nodal elements of each of the pendulums, induced by two pulse jet engines. The pendulums are arranged in line on the platform, aligned with an abstract plane. The plane moves in the direction of its normal using the jet engines. Attachment points of the dual pendulums are selected so that when unfolded their last loads come into contact. Upon simultaneous initiation of oscillations of all pendulums and setting the platform in motion, we consider traces from the spatial displacements of the last loads of pendulums. It is assumed that wire that accepts the shape of the specified traces comes from the last loads and forms the zigzag-like elements of the mesh. In order to fix elements of the mesh, it is suggested that they should be point welded at the moments of contact between the last loads of the pendulums. A description of the inertial unfolding of dual pendulums is compiled using a Lagrange equation of the second kind, in which potential energy was not taken into consideration because of weightlessness. Reliability of the considered geometrical model for weaving a wire cloth was verified in a series of created animated videos that illustrated the process of formation of the elements of a wire cloth. Results might prove useful for designing large-sized structures in weightlessness, for example, antennas for ultralong waves.

Pulsejet engine dynamics in vertical motion using momentum conservation

The momentum conservation law is applied to analyse the dynamics of a pulsejet engine in vertical motion in a uniform gravitational field in the absence of friction. The model predicts the existence of a terminal speed given the frequency of the short pulses. The conditions where the engine does not return to the starting position are identified. The number of short periodic pulses after which the engine returns to the starting position is found to be independent of the exhaust velocity and gravitational field intensity for a certain frequency of pulses. The pulsejet engine and turbojet engine aircraft models of dynamics are compared. Also the octopus dynamics is modelled. The paper is addressed to intermediate undergraduate students of classical mechanics and aerospace engineering.

Experiment Analysis of Combustion Performance in Pulse Jet Engine

Experimental research of a valve pulse-jet engine can provide theoretical support and experimental reference for the development of the engine, which provides practical fundament for the study of the operating characteristics and performance improvement of the small jet engine. An air breathing engine experimental bench including fuel supply system, a test collection system, ignition system, TR-PIV test system had been designed and built for experiment research. And a series of experimental studies on the valve type pulse-jet engine were carried out. The start-up characteristics of the engine in the intake port and combustion chamber under the fuel supply mode of the oil pump were studied. The characteristics of the engine including wall temperature, the concentration of the combustion products, the gas temperature and the pulse pressure were measured by the infrared thermal imaging system, the flue gas analyser and other equipment. The influence of fuel flow on the above parameters was studied.

Research on strap-down seeker guidance information for rolling interceptor

Interceptor usually use direct force control to attack a rapidly maneuvering target. Thus, aircrafts should roll in response to the pulse jet engine. Furthermore, interceptors need a seeker with a simple structure and a rapid tracking rate. Phased-array strap-down seekers can be used for rolling interceptors because of their wide field of view and the absence of a stable platform. However, the disturbance from the interceptors body should be decoupled when phased-array radars are used for strap-down seekers to track rapidly maneuvering targets and thus to calculate the real line-of-sight rate. In this study, the coupling characteristics of the two channels of a spinning interceptors seeker are investigated, and a coupling model is established. The law governing the coupling process is illustrated in consideration of the interceptors motion and seeker parameters. Then, an integrated compensation method that consists of the additive rate compensation method for body disturbance, the cross-decoupling method for rolling movement, and the angle-compensation method for tracking loop dynamic lag is introduced. Finally, a simulation using the proposed method is conducted to validate its efficiency.

Combustion of Acetylene and its Performance in Valveless Pulse Jet Engine

Combustion of Acetylene and its Performance in Valveless Pulse Jet Engine

Performance Estimation for Differential Pressurization Pulse Jet Engine

A novel differential pressurization pulse jet engine is suggested in this paper. Working process of the engine is firstly introduced, then several realistic assumptions are made, physical model and mathematical model of the engine's extrusion and filling process are built. Using Propane as fuel, the mathematical model can be solved by setting some parameters. Working characteristics of the engine in each stage are analysed, and performance parameters of the engine is estimated, such as pressure, thrust, and specific impulse. Through suitably changing several structure parameters, analysing the performance parameters, the impacts of structural parameters on the engine performance are discussed. Finally, compared with conventional pulse jet engines, this engine provides an approach to pressurize and has a higher ratio.