On the Role of Vortex Shedding in Hybrid Rockets Combustion Instability

2008 ◽  
Author(s):  
Carmine Carmicino ◽  
Annamaria Russo Sorge
Keyword(s):  
Vortex Shedding ◽  
Combustion Instability ◽  
Hybrid Rockets

scholarly journals Thrust Force Generated by Heaving Motion of a Plate: The Role of Vortex-Induced Force

2021 ◽  
Author(s):  
Kazuo Matsuuchi
Keyword(s):  
Vortex Shedding ◽  
Thrust Force ◽  
Unsteady Motion ◽  
Force Generation ◽  
Thrust Coefficient ◽  
Momentum Change ◽  
Vortex Element ◽  
Motion Characteristics ◽  
Vortex Systems

To understand the force acting on birds, insects, and fish, we take heaving motion as a simple example. This motion might deviate from the real one. However, since the mechanism of force generation is the vortex shedding due to the motion of an object, the heaving motion is important for understanding the force generated by unsteady motion. The vortices released from the object are closely related to the motion characteristics. To understand the force acting on an object, information about momentum change is necessary. However, in vortex systems, it is impossible to estimate the usual momentum. Instead of the momentum, the “virtual momentum,” or the impulse, is needed to generate the force. For calculating the virtual momentum, we traced all vortices over a whole period, which was carried out by using the vortex-element method. The force was then calculated based on the information on the vortices. We derived the thrust coefficient as a function of the ratio of the heaving to travelling velocity.

Role of Injection in Hybrid Rockets Regression Rate Behaviour

2005 ◽  
Vol 21 (4) ◽  
pp. 606-612 ◽  
Author(s):  
Carmine Carmicino ◽  
Annamaria Russo Sorge
Keyword(s):  
Regression Rate ◽  
Hybrid Rockets ◽  
Rate Behaviour

Investigation on Effect of Inlet Flow Turbulence on the Combustion Instability Using Simultaneous PIV and CH* Chemiluminescence in a Backward Facing Step Combustor

2019 ◽  
Author(s):  
Pankaj Pancharia ◽  
Vikram Ramanan ◽  
Baladandayuthapani Nagarajan ◽  
S. R. Chakravarthy
Keyword(s):  
Turbulence Intensity ◽  
Equivalence Ratio ◽  
Large Scale ◽  
Combustion Instability ◽  
Flow Dynamics ◽  
Airflow Rate ◽  
Backward Facing Step ◽  
Time Resolved ◽  
Flame Holder

Abstract The present study investigates the role of inlet turbulence intensity on the stability characteristics of a lab scale backward facing step combustor (BFS). Turbulence generator placed upstream of the flame holder is used to vary the turbulence levels. The present study utilizes simultaneous chemiluminescence, particle image velocimetry (PIV) and unsteady pressure fluctuation measurement are done in a time-resolved manner to study the role of inlet turbulence intensity on the flame-flow dynamics and identify different modes of combustion instability as a result of the same. The bifurcation plot with airflow rate, in terms of step-based Reynolds number (Re) as the control parameter, indicates a counterintuitive picture, whereby higher turbulence intensity postpones the onset of instability. The finding has been reported in the past by Nagarajan et. al [30], with the present work extending it. It is shown that the flow-flame structures at high (∼1000 Pa) and very high (>4000 Pa), conditions, the dynamics are significantly different across the same turbulence intensity at different equivalence ratio as well as at different turbulence intensities for the same equivalence ratio. Analysis of the flame-flow dynamics reveals the role of the extent of vortex initiated by acoustics and its orientation in forming an unsteady loop, whereby the vortex span and strength aids the flame to propagate upstream of the step, and the flame in-turn being responsible to sustain the large-scale vortex. This phenomenon is distinct from the conventional vortex sustained combustion instability, whereby the vortex is of the lower span and does not influence the upstream flow. The role of inlet turbulence intensity is seen to be more pronounced in the extent of the flame propagating upward, which then completes the fore-mentioned loop.

scholarly journals Onset of nanoscale dissipation in superfluid He4 at zero temperature: Role of vortex shedding and cavitation

2017 ◽  
Vol 96 (6) ◽  
Author(s):  
Francesco Ancilotto ◽  
Manuel Barranco ◽  
Jussi Eloranta ◽  
Martí Pi
Keyword(s):  
Vortex Shedding ◽  
Zero Temperature

scholarly journals Role of Precombustion Chamber Design in Feed-System Coupled Instabilities of Hybrid Rockets

2020 ◽  
Vol 36 (6) ◽  
pp. 796-805
Author(s):  
Jungpyo Lee ◽  
Artur Elias De Morais Bertoldi ◽  
Artem Andrianov ◽  
Renato Alves Borges ◽  
Carlos Alberto Gurgel Veras ◽  
...  
Keyword(s):  
Feed System ◽  
Precombustion Chamber ◽  
Chamber Design ◽  
Hybrid Rockets

Revisiting a Model for Combustion Instability Involving Vortex Shedding

2009 ◽  
Vol 181 (3) ◽  
pp. 457-482 ◽  
Author(s):  
B. Tulsyan ◽  
K. Balasubramanian ◽  
R. I. Sujith
Keyword(s):  
Vortex Shedding ◽  
Combustion Instability

Vortex-driven acoustically coupled combustion instabilities

1987 ◽  
Vol 177 ◽  
pp. 265-292 ◽  
Author(s):  
Thierry J. Poinsot ◽  
Arnaud C. Trouve ◽  
Denis P. Veynante ◽  
Sebastien M. Candel ◽  
Emile J. Esposito
Keyword(s):  
Heat Release ◽  
Vortex Shedding ◽  
Combustion Instability ◽  
Low Frequency ◽  
Combustion Instabilities ◽  
Rayleigh Criterion ◽  
Phase Average ◽  
Steady Heat

Combustion instability is investigated in the case of a multiple inlet combustor with dump. It is shown that low-frequency instabilities are acoustically coupled and occur at the eigenfrequencies of the system. Using spark-schlieren and a special phase-average imaging of the C2-radical emission, the fluid-mechanical processes involved in a vortex-driven mode of instability are investigated. The phase-average images provide maps of the local non-steady heat release. From the data collected on the combustor the processes of vortex shedding, growth, interactions and burning are described. The phases between the pressure, velocity and heat-release fluctuations are determined. The implications of the global Rayleigh criterion are verified and a mechanism for low-frequency vortex-driven instabilities is proposed.

Sign in / Sign up

Export Citation Format

Share Document