• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.75-78
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• 2004

Various jet engines (Turbine engine family and RAM Jet engine) have been developed for high speed aircrafts. but their application to hypersonic flight is restricted by principle problems such as increase of total pressure loss and thermal stress. Therefore, the development of next generation propulsion system for hypersonic aircraft is a very important subject in the aerospace engineering field, SCRAM Jet engine based on a key technology, Supersonic Combustion. is supposed as the best choice for the hypersonic flight. Since Supersonic Combustion requires both rapid ignition and stable flame holding within supersonic air stream, much attention have to be given on the mixing state between air stream and fuel flow. However. the wider diffusion of fuel is expected with less total pressure loss in the supersonic air stream. So. in this study the direction of fuel injection is inclined 30 degree to downstream and the total pressure of jet is controlled for lower penetration height than thickness of boundary layer. Under these flow configuration both streams, fuel and supersonic air stream, would not mix enough. To spread fuel wider into supersonic air an aerodynamic force, baroclinic torque, is adopted. Baroclinic torque is generated by a spatial misalignment between pressure gradient (shock wave plane) and density gradient (mixing layer). A wedge is installed in downstream of injector orifice to induce an oblique shock. The schlieren optical visualization from side transparent wall and the total pressure measurement at exit cross section of combustor estimate how mixing is enhanced by the incidence of shock wave into supersonic boundary layer composed by fuel and air. In this study non-combustionable helium gas is injected with total pressure 0.66㎫ instead of flammable fuel to clarify mixing process. Mach number 1.8. total pressure O.5㎫, total temperature 288K are set up for supersonic air stream.

• Journal of the Korean Wood Science and Technology
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• v.13 no.4
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• pp.3-57
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• 1985

This research was conducted to examine the feasibility of developing fire retardant particleboard and complyboard. Particleboard were manufactured using meranti particle(Shorea spp.)made with Pallmann chipper, and complyboard meranti particle and apitong veneer (Dipterocarpus spp.). Particles were passed through 4mm (6 mesh) and retained on 1mm (25 mesh). Urea formaldehyde resin was added 10 percent on ovendry weight of particle. Face veneer for complyboard was 0.9, 1.6 and 2.3mm in thickness and spread with 36 g/(30.48 cm)$^2$ glue on one side. Veneers were soaked with 10 percent solution of five fire retardant chemicals (diammonium phosphate, ammonium sulfate, monoammonium phosphate, Pyresote and Minalith), and particles with 5, 10, 15 and 20 percent solution of five chemicals. Particleboard and complyboard were evaluated on physical and mechanical properties, and fire retardancy. The results obtained were summarized as follows. 1. Among five fire retardant chemicals treated to particleboard and complyboard, the retention of ammonium sulfate in 5 percent solution showed the lowest as 1.39 kg/(30.48 cm)$^3$ exceeding the minimum retention of 1.125 kg/(30.48 cm)$^3$ recommended by Forest Products Laboratory and Koch. 2. Particleboard and complyboard treated with diammonium phosphate showed higher modulus of rupture (MOR), modulus of elasticity (MOE), internal bond strength and screw holding power than those with the other chemicals. 3. MOR and MOE of complyboard treated with fire retardant chemicals were greater than those of fire retardant particleboard. 4. Thickness swelling of fire retardant complyboard was lower than that of fire retardant particleboard. 5. The moisture content of the boards treated with Pyresote and Minalith increased and with monoammonium phosphate reduced. 6. Fire retardant particleboard showed no ignition, and fire retardant complyboard started ignition, but time required to ignite was prolonged comparing the controlboard. Complyboard with only shell veneer treated showed ignition and lingering flame, but lingering flame time was shorter than controlboard. Complyboard with treated both core and veneer showed ignition but not lingering flame. 7. Flame length, carbonized area and weight loss were smaller than controlboard but had no significant difference among chemicals treated. 8. Temperature of unexposed surface of fire retardant particleboard was lowered with the increasing concentration of five chemicals. 9. Temperature of unexposed surface of fire retardant particleboard was lowered with the highest in Pyresote and the lowest in Minalith. 10. Temperature of unexposed surface of fire retardant complyboard was lower than that of controlboard.