Whether or not the cell number variation meets the integral multiple of halfcell will be demonstrated by checking the total number in each experiment. Gas detonation cell width prediction model based on. Effect of mixture pressure and equivalence ratio on detonation cell. An experimental study on performance of a kerosene based. The pulse width of the detonation pressure for 1hz is analyzed. Introduction the rotating detonation combustor rdc is a continuous detonation. When gas detonation takes place, regularly or irregularly distributed cell structures are observed behind the shock wave.
This is in line with previous experimental findings and numerical predictions. We measured the detonation cell width, velocity and pressure for a range of equivalence ratios in three mixtures. Using cell size data for a few typical fueloxidizer mixtures at standard atmosphere, it is apparent that. D detonation cell width, velocity and pressure for a range of equivalence ratios in three mixtures. Gas detonation cell width prediction model based on support. The cell width, of a detonation is defined as the width of a cell formed by the slipstream associated with the interaction of the transverse and longitudinal waves of the detonation or as the average transverse wave spacing recorded on a sooted foil, is a useful measure of detonation. In this paper we studied various parameters affecting the performance of pulse detonation engine pde like pulse detonation engine tube diameter combustion tube, pulse tube length for proper deflagration to detonation transition ddt, cell size, equivalence ratio of fuel used. Detonation initiated by a shock through a laphragm detonation tube length. Nuregcr5525, hydrogenairdiluent detonation study for.
Us6062018a pulse detonation electrical power generation. Experimental study on transmission of an overdriven detonation wave from propaneoxygen to propaneair j. Mar 18, 2006 the aim of this experimental investigation is the study of deflagration to detonation transition ddt in tubes in order to i reduce both runup distance and time of transition l ddt and t ddt in connection with pulsed detonation engine applications and to ii attempt to scale l ddt with. I have a problem in creating table structure in pdf using fpdf library. As expected, the deviation from the er 1 led to the detonation wave decay, after which the wave velocity. A half cell and then a full cell appear as the channel width increases to 5l 12. A pulse detonation power generation apparatus is provided. If automatic page breaking is enabled and the cell goes beyond the limit, a page break is done before outputting. Relation between cell size and detonation parameters in. Gas detonation cell width prediction model based on support vector. In ddt, the production of turbulence during the long. Experimental measurement of detonation cell size at high pressure.
The detonation cell width is commonly used to measure the ease with which a mixture can be detonated detonation sensitivity or detonability. This may be attributed to the increase in the cell width in. Some numerical issues on simulation of detonation cell structures 561 table 1 survey of numerical studies on the cellular structure of gaseous detonation waves reference, year reactants kinetics domain size grid size simulated cell width initial perturbation oran et al. The pulse detonation energy generator may have one or more detonation chambers, each having an inlet end and an outlet end. Methaneair detonation experiments at niosh lake lynn. One conclusion from this work is that smaller hydrocarbons such as c 2h 2 are not very effective. Detonation physics laboratory gdt 280mm diameter, 7. On the other hand, a fuel with a laminar flame speed lower than 0. Measurements are made of the detonation cell width and detonation wave speed, which provide the necessary data for assessment of mixture sensitivity and lean detonability limits. For case b, the initial pressures in the driver donor, p d1, and the driven donor, p d2, are 0. It is shown that a large reduction in cell size is observed following the frontal collision, and that the detonation cell widths are correlated well with the chemical kinetic calculations from the znd model. No cell was observed for channels with the width smaller than 2. Study of cell width and shock pressure in directly initiated. This paper is aimed to assess the role of boundary layer effect on modifying the detonation cell width of the test gas mixture in the narrow channel.
Based on the characteristic relations, a simple wave intersection model was used to calculate the state of the transmitted. The increase in the detonation cell width by varying the er reduced the detonation or shock velocity, if the detonation wave decayed. The cell width is an intrinsic length scale of a detonation and indicates the sensitivity of a mixture. The images were used to measure the cell width of the hydrogen and air detonations at varying equivalence ratios and mixture pressures. The analysis concerned the detonation cell width, ignition. The detonation in the test gas then propagates down the remaining 15 meters of the vessel. A model for detonation cell size prediction from chemical. This global length scale, referred to as the detonation cell width.
Determination of detonation cell size the first calculation simulated a tube 5 cm high, which we estimated from the experimental data to be smaller than the natural detonation cell size of the 1,7 mixture. Cell width measurements detonation cell width measurements on hydrocarbon fuels have been extremely useful as a simple characterization of fueldetonability. In the gdt, detonation pressure, wave speed and cell width measurements were made in hexaneoxygennitrogen mixtures with and without the addition of lower molecular weight fuels. Detonations occur in both conventional solid and liquid explosives, as well as in reactive gases. Luc a national cheng kung university, institute of aeronautics and astronautics, tainan, taiwan, republic of china. Bosch wideband oxygen sensors precisely measure airfuel. Pdf gas detonation cell width prediction model based on. The initial temperature was varied from 290 k up to 650 k. A condition for stable propagation was determined based on the ratio of.
The issue of grid resolution in simulations of det. Bosch wideband oxygen sensors are designed for an operational life of 100,000 miles. The measured deflagrationto detonation transition composition limits are found to correlate well with the classical detonation propagation criterion based on the detonation cell size a and the. Experimental measurement of detonation cell size at high. Measured quantities d detonation velocity ds l cell length cm deduced parameters tear. Airbreathing rotating detonation wave engine cycle analysis. Figure 3 shows the wave velocity as a function of er. The measured deflagrationtodetonation transition composition limits are found to correlate well with the classical detonation propagation criterion based on the detonation cell size a and the. The charac26 teristic width of these patterns is termed the cell width and provides a measure 27 of the mixture sensitivity to detonation. Numerous criteria have been developed which correlate the possibility of detonation initiation and propagation in a given geometry with the value of the detonation cell width. Detonation from latin detonare, meaning to thunder downforth is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. The formation of detonation fishcell pattern was also recorded by tracking the position of the triple point. Itextsharp how to pass rectangle params to method to set border.
Methaneair detonation experiments at niosh lake lynn laboratory. Detonation cell width measurements for h2n2on2o2ch4nh3 mixtures by u. Table of contents chapter title page declaration i. The velocity of detonation in solid and liquid explosives is. Pulse detonation engine technology has recently emerged as a future aerospace propulsion technology. Study of cell width and shock pressure in directly. Stefanschoch,nikolaosnikiforakis,andlouisamichael arxiv. Structure of a detonation from high speed photography and soot tubes 3d cellular structure, constantly changing cell width. The measured width of primary cells varied between 20 cm near the stoichiometry and 105 cm tube diameter near the limits.
Detonation physics laboratory california institute of. Experimental study on transmission of an overdriven. For ddt to be possible, it has been shown that the mixture detonation cell size must be smaller than some characteristic lengthscale of the apparatus filled with the mixture. An unburnt gas pocket, placed symmetrically behind the planar detonation, generates pressure waves as it burns. The cell width reaches a constant value of about l 12 for channel widths greater than 40l 12.
This differs significantly from the published cell size of 24. Lead shock velocity and curvature variation across the cellular detonation instability scott i. The evolution and cellular structure of a detonation. Another approach was based on analysis of a correlation of reaction zone widths calculated from chemical kinetic models with experimental detonation cell. Analysis of the possibility of, and consequences from. Whether or not the cell number variation meets the integral multiple of half cell will be demonstrated by checking the total number in each experiment. The donor pressure ratio p dp d1p d2 ranges from 1 to 33. Finally, the characteristics of spherical detonation such as the number and width of detonation cells versus distance from the initiation point are calculated from the simulated cellular pattern in fig. Deflection of detonation wave, skewing of cell structure and changes in detonation velocity kessler 2012 n ch 4air shock wavecombustion zone decoupling led to turbulent deflagration ettner 20 n h 2o 2 concentration gradient effected on detonation cell shape, instability, and pressure distribution nordeen 20 n h 2. In this paper we studied various parameters affecting the performance of pulse detonation engine pde like pulse detonation engine tube diameter combustion tube, pulse tube length for proper deflagration to detonation transition ddt,cell size, equivalence ratio of fuel used. Lead shock velocity and curvature variation across the. Effect of mixture concentration inhomogeneity on detonation. Pdf experimental study on cell structure characteristics. The measured cell size is nearly a third of the tube diameter, and there is simply not enough.
The average cell width, measured as the distance between two trajectory intersections in a plane perpendicular to the detona. Correlation of detonation cell widths with detailed chemical reaction mechanisms measurements and models of. In the following analyses a value of h 12 will be used to check for stability. Cell patterns on smokefoils during detonations were very irregular and showed secondary cell structures inside primary cells. The detonation cell width was recorded on a sooted foil lining the inside of the hdt. Bosch wideband oxygen sensors precisely measure airfuel ratios.
Meanwhile, endeavoring thrust comparison between load cell thrust and head end pressure thrust. The detonation velocity and the detonation cell width are determined experimentally as a function of the initial mixing temperature in a valveless pulse detonation combustor pdc. Optimization of the deflagration to detonation transition. Pdf experimental study on cell structure characteristics of. This apparatus is provided with a detonation chamber connected to fuel and air sources which detonate to produce energy which may be converted to electrical energy. The measured cell size for stoichiometric ethyleneair was 9. The formation of detonation fish cell pattern was also recorded by tracking the position of the triple point. Some numerical issues on simulation of detonation cell.
The average width of the cells is defined as the detonation cell width, which is represented by the value of. Figure 3 shows a number and b width of detonation cells in the cases of grid resolution 250 pts. The arrow indicates the direction of propagation of the detonation. Finally the specific impulse of the current pde is investigated with the current available air breathing engines. Gas detonation cell width prediction model based on support vector regression article pdf available in nuclear engineering and technology 497 july 2017 with 21 reads how we measure reads. Pdf detonation cell width is an important parameter in hydrogen explosion assessments. Some numerical issues on simulation of detonation cell structures. A detonation tube facility was originally designed and constructed by raza akbar, pavel svitek, and mike kaneshige. In a previous study,8 various blends of hydrocarbon fuels were examined. In order to estimate possibility for ddt detonation cell sizes.
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