Stability Characteristics of an Actively Valved Resonant Pulse Combustor

2021 ◽  
Author(s):  
Xuren Zhu ◽  
Joel C. Lisanti ◽  
Thibault F. Guiberti ◽  
William Roberts
Keyword(s):  
Pulse Combustor

LES Study of Active Valve Resonant Pulse Combustor

2021 ◽  
Author(s):  
Joel C. Lisanti ◽  
Xuren Zhu ◽  
Thibault Guiberti ◽  
William L. Roberts
Keyword(s):  
Pulse Combustor ◽  
Active Valve

Effects of Tailpipe Friction on the Nonlinear Dynamics of a Thermal Pulse Combustor

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Achintya Mukhopadhyay ◽  
Subhashis Datta ◽  
Dipankar Sanyal
Keyword(s):  
Time Series ◽  
Friction Factor ◽  
Time Series Data ◽  
Threshold Value ◽  
Series Data ◽  
Combustion Dynamics ◽  
Thermal Pulse ◽  
Pulse Combustor ◽  
Steady Combustion ◽  
Peak Pressures

The effect of tailpipe friction on the combustion dynamics inside a thermal pulse combustor has been investigated using a nonlinear model consisting of four coupled first order ordinary differential equations. The dynamics of the system is represented through time series plots, time-delay phase plots, and Poincaré maps. The results indicate that as the tailpipe friction factor is lowered, the system undergoes a transition from steady combustion through oscillating combustion to an intermittent combustion with chaotic characteristics before extinction. The time series data are shown to be useful indicator for early detection of extinction. In one approach (thresholding), the occurrence of local peak pressures below a predefined threshold value is identified as an event and the number of events (event count) and largest number of successive cycles with such events (event duration) are recorded as the friction factor is lowered. In another approach, the statistical moments (kurtosis) of the data are used. Number of kurtosis peaks above a prescribed value and variance of the kurtosis values are recorded for decreasing values of friction factor. All these numbers sharply increase as the system approaches extinction.

Comprehensive Model of a Pulse Combustor

1993 ◽  
Vol 94 (1-6) ◽  
pp. 379-409 ◽  
Author(s):  
THOMAS MOREL
Keyword(s):  
Comprehensive Model ◽  
Pulse Combustor

Optical Analysis of Pulse Combustion Using Shadowgraph and Planar CH-LIF Imaging Technique

2000 ◽  
Vol 123 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Yojiro Ishino ◽  
Tatsuya Hasegawa ◽  
Shigeki Yamaguchi ◽  
Norio Ohiwa
Keyword(s):  
Large Scale ◽  
Ccd Camera ◽  
Pulsation Period ◽  
Planar Imaging ◽  
Camera System ◽  
Band Emission ◽  
Pulse Combustor ◽  
Pulse Combustion ◽  
Combustion Processes ◽  
Ch Radical

Planar imaging of laser-induced fluorescence of CH radical is made to examine combustion processes in a valveless pulse combustor. An excimer-pumped dye laser tuned to a wavelength of 387 nm is used to excite the R1N″=6 line of (0,0) band of the B2Σ−−X2Π system of CH radical, and an image-intensified CCD camera system is used to detect the (0,1) band emission at around 435 nm. According to the CH-LIF images, it is found that the progress in combustion during a pulsation period is expressed by the enlargement and breakup of the earlobe-shaped flame front along the outline of a pair of large-scale eddies of fresh mixture.

Use of Temporal Irreversibility of Symbolic Time Series for Early Detection of Extinction in Thermal Pulse Combustors

2006 ◽  
Author(s):  
Subhashis Datta ◽  
Achintya Mukhopadhyay ◽  
Dipankar Sanyal
Keyword(s):  
Time Series ◽  
Fourth Order ◽  
Time Series Data ◽  
Order System ◽  
Series Data ◽  
Thermal Pulse ◽  
Pulse Combustor ◽  
The Difference ◽  
Symbol Sequences ◽  
System Approaches

A nonlinear fourth-order dynamic model of a thermal pulse combustor has been developed. In this work, the time series data generated by solution of the fourth order system is converted into a set of symbols based on the values of pressure variables. The key step to symbolization involves transformation of the original values to a stream of discretised symbols by partitioning the range of observed values into a finite number of regions and then assigning a symbol to each measurement based on the region in which it falls. Once all the measured values are symbolized, a symbol sequence vector consisting of L successive temporal observations is defined and its relative frequency is determined. In this work, the relative frequencies of different symbol sequences are computed by scanning the time series data in forward and reverse directions. The difference between the relative frequencies obtained in forward and reverse scanning is termed as "irreversibility" of the process. It is observed that for given alphabet and word sizes, the "irreversibility" increases as the system approaches extinction. The effects of different choices of alphabet and word sizes are also considered.

Ion current sensing-based lean blowout detection for a pulse combustor

2017 ◽  
Vol 176 ◽  
pp. 263-271 ◽  
Author(s):  
Fangyan Li ◽  
Lijun Xu ◽  
Minglong Du ◽  
Lijun Yang ◽  
Zhang Cao
Keyword(s):  
Ion Current ◽  
Current Sensing ◽  
Lean Blowout ◽  
Pulse Combustor

Improving the Performance of an Active Valve Resonant Pulse Combustor

2019 ◽  
Author(s):  
Joel C. Lisanti ◽  
Xuren Zhu ◽  
William L. Roberts
Keyword(s):  
Pulse Combustor ◽  
Active Valve
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