Supersonic aircraft

Super slurper Supersonic aircraft fuel Supertarget Super three SUPERTRAP Supplies... 

A smaller factor in ozone depletion is the rising levels of N2O in the atmosphere from combustion and the use of nitrogen-rich fertilizers, since they ate the sources of NO in the stratosphere that can destroy ozone catalyticaHy. Another concern in the depletion of ozone layer, under study by the National Aeronautics and Space Administration (NASA), is a proposed fleet of supersonic aircraft that can inject additional nitrogen oxides, as weU as sulfur dioxide and moisture, into the stratosphere via their exhaust gases (155). Although sulfate aerosols can suppress the amount of nitrogen oxides in the stratosphere... 

Hydraulic and Heat-Transfer Fluids. HydrauHc fluids (qv) for high altitude supersonic aircraft and thermal exchange appHcations including solar panels employ fluids such as tetrakis(2-ethyIhexoxy)silane. These products have been marketed under the trade name Coolanol by Monsanto (see Heat-exchangetechnology). 

Control of nitrogen oxides ia aircraft exhaust is of increa sing concern because nitrogen oxides react with ozone ia the protective layer of atmosphere which exists ia the altitude region where supersonic aircraft operate. Research is under way to produce a new type of combustor which minimizes NO formation. It is an essential component of the advanced propulsion unit needed for a successflil supersonic transport fleet. 

Because of tank heating, fuel volatiUty is also more critical in supersonic aircraft. For example, the Concorde tank is pressurized to prevent vapor losses which could be significant at high altitude where fuel vapor pressure may equal atmospheric pressure. The tank can reach 6.9 kPa (1 psi) at the end of a flight. The need to deoxygenate fuel for thermal stabiUty in the HSCT will doubdess require a similar pressurized system. 

The area rule was one of the most important technical developments during the era of jet-propelled airplanes. Today, almost all transonic and supersonic aircraft incorporate some degree of area rule. For his work on the area rule, Whitcomb received the Collier Trophy, the highest award given in the field of aeronautics. 

All bodies traveling in a fluid experience dynamic heating, the magnitude of which depends upon the body characteristics and the environmental parameters. Modern supersonic aircraft, for example, experience appreciable heating. This incident flux is accommodated by the use of an insulated metallic structure, which provides a near balance between the incident thermal pulse and the heat dissipated by surface radiation. Hence, only a small amount of heat has to be absorbed by mechanisms other than radiation. 

Incendiary munitions for use against supersonic aircraft require rapid initiation of long... 

An additional area of concern with respect to stratospheric ozone is possible direct emissions of NOj into the stratosphere by high-flying supersonic aircraft. This issue has come up repeatedly over the past 20 years, as air travel and pressure from commercial airlines has increased. However, despite substantial research effort to understand stratospheric chemistry, the question is complicated by the changing levels of stratospheric chlorine, first due to a rapid accumulation of tropospheric CFCs, followed by a rapid decline in CFC emissions due to the Montreal Protocol. To quote from the from the 1994 WMO/UN Scientific assessment of ozone depletion, executive summary (WMO 1995) ... 

It is also used as surface coating in supersonic aircraft because it can withstand temperatures as high as 420°C for short time exposures. 

In the late 1960s, direct observations of substantial amounts (3ppb) of nitric acid vapor in the stratosphere were reported. Crutzen [118] reasoned that if HN03 vapor is present in the stratosphere, it could be broken down to a degree to the active oxides of nitrogen NO (NO and N02) and that these oxides could form a catalytic cycle (or the destruction of the ozone). Johnston and Whitten [119] first realized that if this were so, then supersonic aircraft flying in the stratosphere could wreak harm to the ozone balance in the stratosphere. Much of what appears in this section is drawn from an excellent review by Johnston and Whitten [119]. The most pertinent of the possible NO reactions in the atmosphere are... 

It appears that between 15 and 35 km, the oxides of nitrogen are by far the most important agents for maintaining the natural ozone balance. Calculations show that the natural NO should be about 4 X 109 molecules/cm3. The extent to which this concentration would be modified by anthropogenic sources such as supersonic aircraft determines the extent of the danger to the normal ozone balance. It must be stressed that this question is a complex one, since both concentration and distribution are involved (see Johnston and Whitten [119]). 

Briefly, JP-4 is a wide-cut fuel developed for broad availability in times of need. JP-6 is a higher cut than JP-4 and is characterized by fewer impurities. JP-5 is specially blended kerosene, and JP-7 is a high-flash-point special kerosene used in advanced supersonic aircraft. JP-8 is a kerosene fraction that is modeled on jet A-1 fuel (used in civilian aircraft). For this profile, JP-4 will be used as the prototype jet fuel, due to its broad availability and extensive use. 

The FJ test is similar to an aerodynamic wind-turmel test used for supersonic aircraft, except for the airflow condition. A ducted rocket projectile is mounted on a thrust stand and the projectile and thmst stand are placed in a test chamber. A supersonic airflow simulating the flight conditions is suppHed to the projectile through a supersonic nozzle attached to the front-end of the test chamber. The pressure and temperature in the test chamber are kept equivalent to the flight alHtude conditions. The aerodynamic drag on the projectile and the thmst generated by the ducted rocket are measured directly by the FJ test. The airflow surrounding the projectile and the combustion gas expelled from the ramburner flow out from the exhaust pipe attached to the rear-end of the test chamber. 

One recent area of concern has been emissions from potential future supersonic aircraft and from existing rocket and space shuttle launches. The emissions from these sources and their impacts on stratospheric chemistry are the focus of this section. Although continuing development of the HSCT has been halted, the chemistry is relevant and hence is discussed here. 

Concorde Supersonic Aircraft in the Lower Stratosphere, Science, 270, 70-74 (1995a). 

Jones, A. E., S. Bekki, and J. A. Pyle, Sensitivity of Supersonic Aircraft Modelling Studies to HNO, Photolysis Rate, Geophys. Res. Lett., 20, 2231-2234 (1993). 

Weaver, C. J., A. R. Douglass, and D. B. Considine, A 5-Year Simulation of Supersonic Aircraft Emission Transport Using a Three-Dimensional Model, J. Geophys. Res., 101, 20975-20984 (1996). 

The residence times of SO2 and H2S04 in the troposphere are typically only a few days, but sulfuric acid aerosols reaching the stratosphere can be very persistent together with nitric acid, they provide the solid surfaces in polar stratospheric clouds on which reaction 8.9 and related processes occur heterogeneously. Indeed, studies suggest that NOx emissions of commercial supersonic aircraft in the lower stratosphere may pose less of a threat to the ozone layer than previously supposed however, the accompanying formation of sulfuric and nitric acid aerosols may exacerbate ozone loss by increasing the available catalytic surface area. 

THE IMPACT OF NO AND H20 EMISSIONS FROM FUTURE SUB- AND SUPERSONIC AIRCRAFT UPON THE CHEMICAL COMPOSITION OF THE ATMOSPHERE... 

Abstract. The impact of future aircraft emissions on concentrations of reactive nitrogen, water vapour and ozone has been calculated using the 3-dimensional stratospheric chemical transport model SCTM-1. Emissions of NOx (N0+N02) and H20 from both sub- and supersonic aircraft have been considered. 

NOx emissions from subsonic aircraft flying in the troposphere and the lowermost stratosphere lead to a significant increase in ozone in the upper troposphere. Emissions of NOx and H20 from supersonic aircraft cruising in the stratosphere are calculated to decrease the column abundance of O3. The effects of aircraft emissions are found to be strongly dependent on flight altitudes and on assumed emission indices for NOx. 

The scenarios for aircraft emissions are from the NASA data base [1]. Emissions of NOx and water vapour from sub- and supersonic aircraft were considered. For the projected fleet of 500 supersonic aircraft, different emission indices for NOx and cruising altitudes were assumed. 

Figure 1 shows perturbations in water vapour for July. Only in the dry regime of the stratosphere the perturbations can be significant in relative terms. In the maximum, relative increases in zonal mean H2O due to supersonic aircraft are between 10% and 20%, strongly depending on cruising altitudes. 

Figure I Modeled change in zonal mean H20 mixing ratio in July 2015 [ppbv] due to a) subsonic aircraft. The effect of sub- and supersonic aircraft (E.I.NOx=5) combined is shown for different supersonic cruising altitudes b) 16 km, c) 18 km, and d) 20 km.

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