Abstract
Characterization for nonpremixed biodiesel/air jet flames instability is investigated by the 0‐1 test for chaos and recurrence plots. Test conditions involve biodiesel from Jatropha curcas. L‐fueled flames have inlet oil pressure of 0.2–0.6 MPa, fuel flow rates (Q1) of 15–30 kg/h, and combustion air flow rate (Q2) of 150–750 m3/h. This method is based on image analysis and nonlinear dynamics. Structures of flame are analyzed using an image analysis technique to extract position series which are representative of the relative change in temperature of combustion chamber. Compared with the method of maximum Lyapunov exponent, the 0‐1 test succeeds in detecting the presence of regular and chaotic components in flame position series. Periodic and quasiperiodic characteristics are obtained by the Poincaré sections. A common characteristic of regular nonpremixed flame tip position series is detected by recurrence plots. Experimental results show that these flame oscillations follow a route to chaos via periodic and quasiperiodic states.
Highlights
Unsteady motions of the nonpremixed biodiesel-fueled flames in combustion chamber are investigated from the viewpoint of the deterministic chaos theory
Unsteady motions of a nonpremixed biodiesel/air flame tip are experimentally investigated from the viewpoint of nonlinear dynamics
The fuel flow rate is varied from 15 to 30 kg/h, atomization air flow rate is set to a specific value from 0.15 to 0.4 m3/min, and combustion air flow rate is varied from 150 to 750 m3/h
Summary
Unsteady motions of the nonpremixed biodiesel-fueled flames in combustion chamber are investigated from the viewpoint of the deterministic chaos theory. The periodic and chaotic motions in flame dynamics that can be observed as a result of flame instabilities are of great importance to present-day combustion physics and thermal fluid science research 1 ; they are significant in problems that involve combustion instabilities within engines, boilers, and furnaces. The combustion process is characterized by the coupling of various nonlinear phenomena, leading to the formation of either a limit. Mathematical Problems in Engineering cycle or chaos. There are three ways leading to chaos: period-doubling bifurcation, intermittent chaos, and quasiperiodic into chaotic. Fichera et al 2 have verified that combustion instability is governed by chaos, using the nonlinear time series analysis techniques, stable combustion system means that the system is pushed towards chaotic regimes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
