Component Analysis of TBCC Propulsion for a Mach 4.5 Supersonic Cruise Airliner

This paper describes the status of the study on component analysis for the different Variable TBCC cycle configurations. The paper investigates different Variable Cycle TBCC configurations and compares them with an advanced turbojet for the generic configuration of a Mach 4.5 supersonic passenger airliner. One VCE engine variant and the turbojet are preliminarily designed and their mass including airintake and nozzle is estimated. The air-intake has been preliminarily sized and pressure recovery and mass flow in design and off-design conditions is estimated. The intake's dimension and airflow data have been subsequently delivered for further analyses. Engine weight analysis is also conducted both for existing engines and proposed LAPCAT turbo engines

Preliminary Definition of a TBCC Propulsion System for a Mach 4.5 Supersonic Cruise Airliner

The paper investigates different Variable Cycle TBCC configurations and compares them with an advanced turbojet for the generic configuration of a Mach 4.5 supersonic passenger airliner. One VCE engine variant and the turbojet are preliminarily designed and their mass including air-intake and nozzle is estimated. The airintake has been sized and pressure recovery and mass flow in design and off-design conditions is estimated and subsequently checked by the Navier-Stokes CFD code Argo

Laser Induced Ignition and Plasma Spectroscopy (LI2PS) Applied to a Non-premixed Hydrogen-air Combustor

International audienceLaser induced ignition has a potential for several applications such as upper-stage rocket engine ignition device because of its possible high reliability. The laser induced ignition itself has several strong points such as accurate time and impinged energy evaluation capability. The present combined Laser Induced Ignition and Plasma Spectroscopy (LI2PS) have additional potential of measurement to the above-mentioned laser induced ignition in terms of exact local composition of the mixture at the ignition point and for the ignition time. Because the classical power meter classification is not suitable for the present gaseous composite measurement methodology, a novel calibration scheme is proposed for gaseous analysis. We tested non-reactive (helium) case and reactive and ignition (hydrogen) case with a small hydrogen-air burner which is a single injector model of the scaled hypersonic engine under development. At first, the overall capabilities of the gaseous composite measurement are demonstrated with helium as the simulated fuel composite. It is shown that the calibration requires only on the dependencies such as of nitrogen excitation and nitrogen-hydrogen ratio without power meter requirements. Then to illustrate the use of such single shot approach to the combined ignition and plasma spectroscopy case, this methodology is applied to a non-premixed hydrogen-air burner. In this case, the calibration is based on hydrogen excitation and hydrogen-oxygen and hydrogen-nitrogen ratio. Results showed that the local gaseous measurements well correspond to the success/failure criteria, which can not be clearly seen in the past measurement of global fuel equivalence ratio. This result shows that the presently introduced LI2PS would become an important tool when dealing with partially premixed or diffusion flame ignition

Combined Laser Induced Ignition and Plasma Spectroscopy: Fundamentals and Application to a Hydrogen-Air Combustor

International audienceCombined Laser Induced Ignition and Plasma Spectroscopy (LI2PS) has the potential to give the exact local composition of a mixture at the ignition point and at the ignition time. However, as different laser energies are required to ignite a particular mixture as function of space, the typical approach using two power meters to calibrate the plasma spectroscopy measurement is not well suited. Furthermore, LI2PS requires single shot measurements and therefore high accuracy. In this paper, a novel calibration scheme is presented for application of Laser Induced Plasma Spectroscopy (LIPS) to gaseous analyses. Numerical simulations of air spectra are used to show that species emission can be used directly from the broadband spectra to determine the plasma conditions. The ratio of nitrogen emission around 744 nm and around 870 nm is found to be a sensitive indication of temperature in the emission ranging from 700 to 890 nm. Comparisons with experimental spectra show identical tendencies and validate the findings of the simulations. This approach is used in a partially-premixed hydrogen–air burner. First, helium is used instead of hydrogen. After an explanation of timing issue related to LIPS, it is shown that the calibration required depends only on nitrogen excitation and nitrogen–hydrogen ratio, without the need to know the deposited power. Measurements of the fuel distribution as function of injection momentum and spatial localization are reported. To illustrate the use of such a single shot approach, combined laser ignition and plasma spectroscopy is proposed. In this case, the calibration is based on hydrogen excitation and hydrogen–oxygen and hydrogen–nitrogen ratio. Results obtained with LI2PS show that ignition is successful only for high power and relatively high hydrogen concentration compared to the local mean. It is expected that LI2PS will become an important tool when dealing with partially-premixed or diffusion flame ignition

Interaction Effects on Combustion of Alcohol Droplet Pairs

Experimental investigation was conducted on two droplet-array combustion of methanol and methanol/dodecanol mixture fuels in microgravity. For methanol, effects of ambient pressure and droplet spacing were examined. Results show that the droplet lifetime decreases with increasing spacing at relatively low pressure and the droplet lifetime becomes independent of spacing at higher-subcritical and supercritical pressures. For methanol/dodecanol mixture, effects of pressure, fuel composition were investigated in terms of occurrence of disruption. Disruption of droplet during combustion was demonstrated both for single droplet and droplet pairs