Technical seminar on chevron nozzles
•Download as PPTX, PDF•
7 likes•2,674 views
the are the new invention by nasa group which are used to reduce the noise polution that are coming from engine of the aircrafts
Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (18)
Similar to Technical seminar on chevron nozzles
Similar to Technical seminar on chevron nozzles (20)
Recently uploaded
Recently uploaded (20)
Technical seminar on chevron nozzles
- 1. TECHNICAL SEMINAR REVIEW ON “ CHEVRON NOZZLES “ BY G.V.SESHASAI 12Q91A2107 DEPT. OF AERO
- 2. Scope Of The Project The strict noise regulations around major airports due to environmental concern have made jet noise a crucial problem in present day aero-acoustics research. The three main acoustic sources in aircraft are aerodynamics noise, noise from aircraft systems and engine and mechanical noise. Among these noise sources engine noise contribute more noise pollution to environment.
- 3. NOISE REDUCTION METHOD • Chevron nozzles Chevrons are the saw tooth patterns on the trailing edges of some jet engine nozzles that are used for noise reduction.
- 4. DESIGN OF ROUNDED NOZZLE In the current study, a 3” diameter round converging- diverging (CD) supersonic nozzle was designed using a method-of- characteristics to provide ideal expansion or shock free flow at the nozzle exit. Figure 2 shows a schematic of the round nozzle interior contour and a photo of the nozzle mounted at the termination of the ART centerline piping. The screen located upstream of the nozzle in the photo covers the suction system used to control boundary layer thickness on the exterior of the piping leading to the nozzle. A secondary flow pipe used for dual stream jet noise studies is embedded behind the screen although it is capped off in the current configuration. S
- 5. DESIGN OF CHEVRON NOZZLE A chevron nozzle was also designed as a variant of the mj=1.5 CD nozzle. The chevrons are configured as extensions to the 3” diameter CD nozzle with a one degree angle of penetration into the flow. Figure 3 shows a schematic of the nozzle interior contour and a photo of the chevron nozzle. The nozzle equivalent exit area, represented by the projected downstream area, is reduced by 6% due to the penetration.
- 6. DESIGN IMPORTANCE The comprehensives experimental studies at NASA reveal that the chevron modification to the round nozzle can bring as much as 3 db reduction in peak noise during take-off with less than 0.5 % thrust loss during cruise. They reported that for high frequencies and large angles to the jet, the use of chevrons may also lead about to 2 db noise increase.
- 7. COMPARISON OF NOISE REDUCTION RESULTS
- 11. RESULTS DISCUSSION It is apparent from the numerical results presented here so far that a nozzle with chevron shows an appreciable sound reduction of the supersonic jet on the order of 4.13% while comparing with the base model with 0.6% thrust loss. While comparing with other chevron nozzles we have observed that chevron nozzles shows higher acoustic level than the base model. It indicates that chevron nozzles will defeat the very purpose of its objective for jet noise reduction. We comprehended that prudent selection of chevron geometry is a meaningful objective for the jet noise reduction without scuttling the vehicle performance.
- 12. CONCLUSION We have concluded that the shape optimizations of chevron nozzle have a potential for reduction of turbulent mixing noise, which is believed to be the dominant component of jet noise for most aircraft. We also concluded that the chevron is the best choice for the sound reduction, of the acoustic power level of the base model of the nozzle, on the order of 6 db. We also concluded that the prudent selection of chevron will enable the designer to reduce the sound level on the order of ~5%. It is emphasized that jet noise remains a major component of engine noise and the chevron technology has provided a modest relief for jet noise reduction in aerospace applications.
- 13. THAN………Q