Effects of pulsed injection on ignition delay and combustion performance in a hydrogen-fuel scramjet combustor

2022 ◽  
Author(s):  
Zan He ◽  
Ye Tian ◽  
Jialing Le ◽  
Fuyu Zhong
Keyword(s):  
Ignition Delay ◽  
Hydrogen Fuel ◽  
Combustion Performance ◽  
Scramjet Combustor ◽  
Pulsed Injection

Study on the Combustion Chemical Reaction of Biodiesel Fuel for the Improvement of Compression Ignition Combustion Performance

2017 ◽  
Author(s):  
Young Chan Lim ◽  
Hyun Kyu Suh
Keyword(s):  
Chemical Reaction ◽  
Ignition Delay ◽  
Equivalence Ratio ◽  
Combustion Temperature ◽  
Numerical Study ◽  
Constant Volume ◽  
Biodiesel Fuel ◽  
Compression Ignition ◽  
Combustion Performance ◽  
Compression Ignition Combustion

Numerical study on the combustion chemical reaction of biodiesel fuel for the improvement of compression ignition combustion performance was studied in this work. The constant volume closed homogeneous reactor model was applied, at the same time, analysis conditions were set to 700∼900K of ambient temperature, and 15atm of ambient pressure. Also, the equivalence ratio was changed from 0.5 to 1.4 under the various mixing ratio, respectively. The results of analysis were compared in terms of ignition delay, combustion temperature, combustion pressure, NOx and CO emissions. Also, the total mass and the mass densities of the reactants were compared in the constant volume chamber. It was revealed that the value of ignition delay became shorter and combustion temperature and pressure were increased under the rich combustion conditions (Φ > 1.0). Furthermore, the CO emission was decreased under the lean combustion conditions (1.0 > Φ). Maximum value of NOx emission was observed when the equivalence ratio was 0.8 condition since the nitrogen and oxygen chemical reactions became actively than other cases.

scholarly journals Direct Measurements of Skin Friction in Supersonic Combustion Flow Fields

1992 ◽  
Author(s):  
K. M. Chadwick ◽  
D. J. Deturris ◽  
J. A. Schetz
Keyword(s):  
Skin Friction ◽  
Fuel Injection ◽  
Force Measurement ◽  
Tangential Force ◽  
Transverse Component ◽  
Supersonic Combustion ◽  
Quartz Tube ◽  
Hydrogen Fuel ◽  
Sensor Head ◽  
Scramjet Combustor

An experimental investigation was conducted to measure skin friction along the chamber walls of supersonic combustors. A direct force measurement device was used to simultaneously measure an axial and transverse component of the small tangential shear force passing over a non-intrusive floating element. This measurement was made possible with a sensitive piezoresistive deflection sensing unit. The floating head is mounted to a stiff cantilever beam arrangement with deflection due to the flow on the order of 0.00254 mm (0.0001 in). This allowed the instrument to be a non-nulling type. A second gauge was designed with active cooling of the floating sensor head to eliminate non-uniform temperature effects between the sensor head and the surrounding wall. The key to this device is the use of a quartz tube cantilever with piezoresistive strain gages bonded directly to its surface. A symmetric fluid flow was developed inside the quartz tube to provide cooling to the backside of the floating head. Tests showed that this flow did not influence the tangential force measurement. Measurements were made in three separate combustor test facilities. Tests at NASA Langley Research Center consisted of a Mach 3.0 vitiated air flow with hydrogen fuel injection at Pt = 500 psia (3446 kPa) and Tt = 3000 R (1667 K). Two separate sets of tests were conducted at the General Applied Science Laboratory (GASL) in a scramjet combustor model with hydrogen fuel injection in vitiated air at Mach = 3.3, Pt = 800 psia (5510 kPa), and Tt = 4000 R (2222 K). Skin friction coefficients between 0.001–0.005 were measured dependent on the facility and measurement location. Analysis of the measurement uncertainties indicate an accuracy to within ±10–15% of the streamwise component.

scholarly journals Study on Diesel Low-Nitrogen or Nitrogen-Free Combustion Performance in Constant Volume Combustion Vessels and Contributory

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 923
Author(s):  
Qinming Tan ◽  
Yihuai Hu ◽  
Zhiwen Tan
Keyword(s):  
Ignition Delay ◽  
High Speed ◽  
Delay Period ◽  
Constant Volume ◽  
Combustion Performance ◽  
Combustion Flame ◽  
O2 Concentration ◽  
Constant Volume Combustion ◽  
Low Nitrogen ◽  
Ignition Delay Period

This paper studies the combustion performance of diesel in constant volume combustion vessels under different conditions of mixed low-nitrogen (O2 and N2) or non-nitrogen (O2 and CO2) in varying proportions. The high-speed camera is used to shoot the combustion flame in the constant volume combustion vessel. The process and morphology of the combustion flame are amplified in both time and space to study and analyze the effects of different compositions and concentrations in gases on the combustion performance of diesel and conduct a study on the contributory factors in the performance of diesel with no nitrogen. According to the study, in the condition of low nitrogen, the O2 concentration is more than 60%, the ignition delay period is shortened, the combustion flame is bright and slender, it spreads quickly, and the blue flame appears when the O2 concentration reaches 70%; While for nitrogen-free combustion, only when the O2 concentration reaches 30% is the combustion close to the air condition; when the O2 concentration reaches 40%, the combustion condition is optimized obviously and the combustion flame is relatively slender compared to the air working condition. Similarly, with the increase of the O2 concentration, the ignition delay period of nitrogen-free diesel is shortened, the duration is extended, and the combustion performance is optimized. In addition, when the O2 concentration reaches 50%, with the decrease of the initial temperature, the ignition delay period is prolonged, and the duration is shortened obviously. When the temperature is lower than 700 K, there is no ignition. The increase of the diesel injection pressure is beneficial to optimize the ignition performance of diesel non-nitrogen combustion and shorten its ignition delay period and combustion duration. Related research has important guiding significance to optimize nitrogen-free combustion technology, which produces no NOx of the diesel engine.

The Influence of Supersonic Combustion when the Cavity Parameters Changed on the Chamber Wall

2012 ◽  
Vol 468-471 ◽  
pp. 2620-2623
Author(s):  
Peng Gao ◽  
Xin Long Chang ◽  
Shuang Lin Gao ◽  
Jie Tang Zhu
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
High Efficiency ◽  
Supersonic Combustion ◽  
Chamber Wall ◽  
Flame Stability ◽  
Hydrogen Fuel ◽  
Research Results ◽  
Scramjet Combustor ◽  
Air Mixing

In this paper, the detail numerical simulations were performed on the flow field of the scramjet combustor chamber with the hydrogen fuel, when the cavity parameters changed. The research results indicate that the effect of gas and air mixing and flame stability are altered when the parameter of cavity changed. From the research we will better understand the supersonic combustion. The high efficiency flame stabilities can be designed in future.

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