scholarly journals Longitudinal Combustion Instability in a Rocket Engine with a Single Coaxial Injector

2018 ◽  
Vol 34 (2) ◽  
pp. 354-373 ◽  
Author(s):  
Tuan M. Nguyen ◽  
Pavel P. Popov ◽  
William A. Sirignano
Keyword(s):  
Rocket Engine ◽  
Combustion Instability ◽  
Coaxial Injector

scholarly journals Effect of excitation on gas centered swirl coaxial injectors

2017 ◽  
Author(s):  
Youngbin Yoon ◽  
Gujeong Park ◽  
Sukil Oh ◽  
Jinhyun Bae
Keyword(s):  
Momentum Flux ◽  
Rocket Engine ◽  
Combustion Instability ◽  
Electrical Conductance ◽  
Flux Ratio ◽  
Xenon Lamp ◽  
Momentum Flux Ratio ◽  
Conductance Method ◽  
Liquid Rocket ◽  
Coaxial Injector

Studies on combustion instability in liquid rocket engines are important in improving combustion efficiency andpreventing combustion chamber losses. To prevent combustion instability, methods such as baffles and cavities are used. The injector is located in the middle of the perturbation-propagation process in the rocket engine, so it is important to study the suppression of combustion instability using the design of the injector. Much research has been focused on the study of liquid excitation in a single injector; however, the actual injector used in a liquid rocket engine is a coaxial injector. In this study, the dynamic characteristics of a gas-centred swirl coaxial injector were investigated by varying the gap thickness and momentum-flux ratio. Spray photographs were captured by synchronizing a stroboscope and digital camera, and a high-speed camera and Xenon lamp were also used. To measure the liquid film, a measurement system was implemented using the electrical conductance method. For excitation of the gas, an acoustic speaker was used to impart a frequency to the gas. The gGas velocity and effect of excitation were measured by hot-wire anemometry. A mechanical pulsator was used for liquid flow excitation. Liquid fluctuation was measured by a dynamic pressure sensor. In both gas and liquid excitation cases, the gain increased as the gap thickness decreased and the momentum-flux ratio increased. From these results, it can be concluded that gap thickness and momentum-flux ratio are major factors in suppressing combustioninstability. DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4653

scholarly journals Low-Probability Events Leading to Rocket Engine Combustion Instability

AIAA Journal ◽  
2017 ◽  
Vol 55 (3) ◽  
pp. 919-929 ◽  
Author(s):  
Pavel P. Popov ◽  
Athanasios Sideris ◽  
William A. Sirignano
Keyword(s):  
Rocket Engine ◽  
Combustion Instability ◽  
Engine Combustion ◽  
Low Probability

scholarly journals Spray and atomization characteristics of gas-centered swirl coaxial injectors

2016 ◽  
Vol 9 (2) ◽  
pp. 127-140 ◽  
Author(s):  
Rahul Anand ◽  
PR Ajayalal ◽  
Vikash Kumar ◽  
A Salih ◽  
K Nandakumar
Keyword(s):  
Rocket Engine ◽  
Cone Angle ◽  
Spray Angle ◽  
Rocket Engines ◽  
Sauter Mean Diameter ◽  
Swirl Number ◽  
Spray Cone ◽  
Mean Diameter ◽  
Atomization Characteristics ◽  
Coaxial Injector

To achieve uniform and efficient combustion in a rocket engine, a fine uniform spray is needed. The same is achieved by designing an injector with good atomization characteristics. Gas-centered swirl coaxial (GCSC) injector elements have been preferred recently in liquid rocket engines because of an inherent capability to dampen the pressure oscillations in the thrust chamber. The gas-centered swirl coaxial injector chosen for this study is proposed to be used in a semi-cryogenic rocket engine operating with oxidizer rich hot exhaust gases from the pre-burner and liquid kerosene as fuel. In this paper, nine different configurations of gas-centered swirl coaxial injector, sorted out by studying the spray angle and coefficient of discharge with swirl number varying from 9 to 20 and recess ratio of 0.5, 1, and 1.5 are investigated for their atomization characteristics. Spray uniformity, spray cone angle, and droplet size in terms of Sauter mean diameter and mass median diameter are studied at various momentum flux ratios for all configurations. Sauter mean diameter is almost independent of recess ratio, whereas cone angle was inversely proportional to the recess ratio. A finer atomization was observed for injectors of high swirl number but the pressure drop also increased to achieve the same flow rate. An injector of medium swirl number and recess ratio of 1.5 is deemed most fit for above-mentioned application.

Rocket engine coaxial injector liquid/gas interface flow phenomena

1995 ◽  
Vol 11 (3) ◽  
pp. 513-518 ◽  
Author(s):  
Wolfgang Mayer ◽  
Gerd Krulle
Keyword(s):  
Rocket Engine ◽  
Flow Phenomena ◽  
Coaxial Injector
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