Aerodynamic heating

Fig. 2. A simplified material thermal performance analysis for a reentry vehicle thermal protection system where = density x surface recession thickness = total aerodynamic heat/heat of ablation ...

Aerodynamics deals with the flow of gases, particularly air, and the interaction with objects immersed in the flow. The interaction takes the form of an aerodynamic force and moment exerted on the object by the flow, as well as heat transfer to the object (aerodynamic heating) when the flow velocities exceed several times the speed of sound. 

Advanced two- and three-dimensional computer analysis methods are used today in the analyses of all critical components to verify aerodynamic, heat transfer, and mechanical performance. Additionally, the reduction of leakage paths in the compressor, as well as in the gas turbine expander, results in further plant efficiency improvements. At the compressor inlet, an advanced inlet flow design improves efficiency by reducing pressure loss. Rotor air cooler heat utilization and adt anccd blade and vane cooling arc also used. 

The explosives used for military purposes are different from those used in industry. Not only thermo mechanical power for destruction, but also various other characteristics are required. Experimental tests, such as slow cook-off fast cook-off, bullet impact, and sympathetic explosion tests, must be passed to meet the requirements for insensitive munitions (IM). The aerodynamic heating of warheads on flight projectiles is also an important factor in designing warheads. 

At high Re and Ma in the free-molecule regime, transfer rates for spheres have been calculated by Sauer (S4). These results, together with others for cylinders and plates, have been summarized by Schaaf and Chambre (Sll). The particles are subject to aerodynamic heating and the heat transfer coefficients are based upon the difference between the particle surface temperature and the recovery temperature (see standard aerodynamics texts). In the transitional region, the semiempirical result of Kavanau (K2),... 

In supersonic missiles where warheads are subjected to aerodynamic heating, conventional explosives cannot be used and thermally stable explosives like TATB, TACOT, HNS and PYX, etc. are necessary for such systems. Some formulations based on these explosives are HNS/Kel-F800 95/5 (developed by Atomic Weapons Research Establishment, Aldermaston, UK) and AFX 521 (PYX/Kel-F800 95/5 — developed by Los Alamos National Laboratory, USA). Their shock sensitivities lie in the region required for boosters. HNS/Teflon explosive charges have also been used for the Apollo 17 seismic experiments [199]. 

One of the more extreme environmental conditions experienced by an epoxy composite matrix occurs during a suspersonie dash of a fighter aircraft. The aircraft dives from high altitudes (where outer surface temperature is —20 to —55 °C) into a supersonic, low-altitude run during which aerodynamic heating raises the surface temperature to 100-150 °C, in a matter of minutes. On reduction of speed, the outer... 

Aerodynamic heating will present problems concerning the thermal stability of fuels, as they will probably be used as a heat sink on aircraft. The fuels will be susceptible to evaporation and thermal decomposition at the temperatures and duration of time to which they will be exposed. Considerable effort 25, 81, 102, 135) is now being devoted to this field. 

Truitt, R.W., Fundamentals of Aerodynamic Heating, Ronald Press, New York, 1960. 

Rubesin, M.W. and Johnson, H.A., Aerodynamic Heating and Convective Heat Transfer— Summary of Literature Survey , Trans. ASME, Vol. 71, pp. 383-388,1949. 

Suppose a flat plate is exposed to a high-speed environment. We define the radiation equilibrium temperature of the plate as that temperature it would attain if insulated so that the energy received by aerodynamic heating is just equal to the heat lost by radiation to the surroundings, i.e.,... 

Data on complex thermogravimetric analysis at aerodynamic heating are given in Table29. 

The aerodynamic heating associated with the flow of air towards the impactor surface must be small enough not to cause droplet evaporation. 

As a numerical example, the cases as seen in aerodynamic heating are analyzed. The influence of functionally graded Young s modulus and temperature change on the large deflection are shown in the graphs. 

In case of / = 0, this equation becomes the same equation as Eq. 26 of [10] and for aerodynamic heating with a uniform load, q(x,y) = q, it becomes as follows... 

M. Sunakawa, Thermal Deformation of Clamped Rectangular Plate Subjected to Aerodynamic Heating, Transaction of the Japan Society of Mechanical Engineers, Vol, 9, No. 85, (1961) 37 (Japanese). 

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