Environmental Impact of Aviation Flashcards
sound waves
oscillations of the air that can be heard by human ear or measured by physical device
progresses as a periodic oscillation of the air density through longitudinal waves
characterized by a local speed of sound and local sound pressure
amplitude is loudness
sound pressure level
reference 2*10^-5 Pa
sound intensity
quantitative physical metric to address the energy transport of a sound wave
noise
subjective evaluation of the degree of annoyance of sound
current maximum levels
perceived noise level (PNL) measure of the current noise level determined by empirical weighting of the intensities of multiple frequency bands relative to the overall noise level
tone corrected perceived noise level (PNLT): addition of tone correction for tone noise in the frequency spectrum
a-weighted sound pressure level (La): evaluation of the current noise level according to the A-weighting curve
maximum level for one event
effective perceived noise level (EPNL): measure of the noise level taking into account the chronological sequence of a sound event.
sound exposure level (SEL)
same as EPNL but without tone correction and taking the A-weighted sound pressure level as a basis
level for multiple events
weighted equivalent continuous perceived noise level (WECPNL): measure of annoyance of noise at an airport through the integration of measured EPNL during one year
energy equivalent constant sound pressure (Leq): measure of noise emission during one day on basis of SEL (europe)
day-night level (DNL): measure of noise emission during one day on basis on the SEL (america)
positioning for noise certifications
approach (2k from runway threshold under approach flight path)
sideline (highest noise measurement recorded at any point 450m from the runway axis during takeoff)
fly-over (6.5 km from the brake release point under the takeoff flight path)
ICAO noise regulations ch 14
increase in stringency of 7 EPNdB relative to chapter 4
applicable to new types submitted for certification on or after 31 december 2017
source of sounds
engine noise during takeoff structure noise during landing
noise mitigation short term
experimental methods aimed at optimizing the noise characteristics of landing gear and high lift devices
noise mitigation long term
calculation of noise emissions and local distribution through CAA (computational aeroacoustics), noise focused optimization through numerical simulation of various configurations
night curfews
predominant at european airports, one runway closed, max noise levels
limitation of noise level
flying ban / penalty charges when a certain noise level is exceeded
quota regulations
max number of flights per airline/time interval according to noise
noise charges
based on noise level, time of departure/arrival, and season
noise reducing procedures
thrust cutback, steep approach/takeoff procedures
emission index
indicate the quantity of a specific pollutant per kilogram of jet fuel burned
ICAO landing and takeoff (LTO) cycle
local air quality emissions from MSL to 3000ft, emissions measurements are referenced to LTO cycle, simple estimation calculations, model cycle and does not capture pilot behavior
ozone health
lung function impairment, effects on exercise performance, lung structure damage
carbon monoxide health
cardiovascular effects
nitrogen oxides health
lung irritation and lower resistance to respiratory functions
particulate matter health
premature mortality, aggravation of respiratory and cardiovascular disease, lung function, lung tissue
volatile organic compounds health
eye and respiratory tract irritation, headaches, dizziness, visual disorders, memory impairment
ozone environment
crop damage, tree damage
carbon monoxide environment
similar health effects on animals as on humans
nitrogen oxides environment
acid rain, visibility, particle formation
particulate matter environment
visibility, building soiling, safety for aircraft
volatile organic compounds environment
contribution towards ozone formation, odors, buildings and plants
means of environmental protection
ICAO annex 16 vol. 2 limits NOx, CO, HC, and soot
emissions depending landing fees
emission fees, environmental charge per passenger
CO2 compensation charges to passengers
european emissions trading system
kerosene tax
ICAO annex 16 vol. 2 engine emission certification
applicable for all engines with a rated output exceeding 26.7 kN being produced after jan 1, 1983
referenced to MSL and ISA
mandatory requirement of all ICAO member states
european emissions trading system (EUETS)
integrate commercial aviation into system from 2012
partially open (can by certificates from sectors other than aviation)
only CO2 emissions taken into account
aviation sector receives certificates representing 97% of average CO2 emissions produced yearly within 2004-2006, budget will be lowered to 95% from 2013 to 2020
current state EUETS jan 2015
prices for certificates much lower than originally anticipated (almost no incentives for companies to lower emissions), only european domestic flights, waiting for ICAO to make international scheme
reducing engine emissions
increase specific fuel consumption, combustion chambers with low NOx production, optimization of the joule-brayton process, alternative fuels
intercooled recuperated core
intercooler located between low and high pressure compressor, use of exhaust heat exchanger, low overall pressure ratio (25)
advantages: very high thermal efficiency, low NOx, 30% fuel burn reduction, technological maturity expected 2035
challenges: integration of intercooler and exhaust recuperator, low pressure losses, light weight and reliable system parts
reducing emissions design
aerodynamics reduce drag (blended winglets, advanced wing profiles, hybrid laminar flow control, adaptive wing)
structure reduce weight
configurations reduce weight and drag
reducing emissions operations
optimized air traffic management, low emissions terminal procedures, low emissions airport operations
greener by design
increase L/D, wing span up, wing weight up
radical approaches: blended wing body, natural laminar flow control, hybrid laminar flow control, full laminar flow control
