Journal of the Korean Society of Propulsion Engineers, 2018
This paper summarizes the technical difficulties pertaining the double-compression ramp scramjet ... more This paper summarizes the technical difficulties pertaining the double-compression ramp scramjet inlet model testing in a shock tunnel and their corresponding solutions. Four technical difficulties are identified: 1) test facility unstart, 2) flow disturbance and model damage due to the impact of diaphragm debris, 3) lack of fuel jet development due to multiple injection, and 4) short test time. After overcoming the identified technical difficulties, the improved results were confirmed through the results of shadowgraph images and shock tube end wall pressure.
The flameholding characteristics of a model scramjet were investigated experimentally. Experiment... more The flameholding characteristics of a model scramjet were investigated experimentally. Experiments were performed in a shock tunnel at a nominal freestream Mach number of 4. The considered total enthalpy was approximately 1.7 MJ/kg. The test model consisted of a double ramp inlet, combustor with cavity, and cowl. The investigated fuel was ethylene, with a fuel-air equivalence ratio ranging from 0.05 to 0.21. Shadowgraph and flame luminescence images were obtained. The effects of injection location, angle, and equivalence ratio on flameholding were investigated. As the equivalence ratio was increased, the flame signals in the cavity shear layer strengthened with a near-constant spreading angle for inlet injection. The flame was maintained at the shear
This paper introduces the method how to measure the thrust in impulse facility. In a Facility hav... more This paper introduces the method how to measure the thrust in impulse facility. In a Facility having such a short duration time of steady flow, there’s no time to reach a steady state of the forces acting on model so that the test model vibrates until the end of the flow. The forces exerted on an engine exist with vibration so that the usual force balance can not be used. SWFB(Stress Wave Force Balance) technique is utilized in a shock tunnel to get the thrust. As an example, a model force balance has been calculated its strain against impulse force by using FEM(Finite Element Method). A transfer function between the impulse force and strain has been obtained by the way of de-convolution.
Journal of the Korean Society of Propulsion Engineers, 2018
This paper summarizes the technical difficulties pertaining the double-compression ramp scramjet ... more This paper summarizes the technical difficulties pertaining the double-compression ramp scramjet inlet model testing in a shock tunnel and their corresponding solutions. Four technical difficulties are identified: 1) test facility unstart, 2) flow disturbance and model damage due to the impact of diaphragm debris, 3) lack of fuel jet development due to multiple injection, and 4) short test time. After overcoming the identified technical difficulties, the improved results were confirmed through the results of shadowgraph images and shock tube end wall pressure.
The flameholding characteristics of a model scramjet were investigated experimentally. Experiment... more The flameholding characteristics of a model scramjet were investigated experimentally. Experiments were performed in a shock tunnel at a nominal freestream Mach number of 4. The considered total enthalpy was approximately 1.7 MJ/kg. The test model consisted of a double ramp inlet, combustor with cavity, and cowl. The investigated fuel was ethylene, with a fuel-air equivalence ratio ranging from 0.05 to 0.21. Shadowgraph and flame luminescence images were obtained. The effects of injection location, angle, and equivalence ratio on flameholding were investigated. As the equivalence ratio was increased, the flame signals in the cavity shear layer strengthened with a near-constant spreading angle for inlet injection. The flame was maintained at the shear
This paper introduces the method how to measure the thrust in impulse facility. In a Facility hav... more This paper introduces the method how to measure the thrust in impulse facility. In a Facility having such a short duration time of steady flow, there’s no time to reach a steady state of the forces acting on model so that the test model vibrates until the end of the flow. The forces exerted on an engine exist with vibration so that the usual force balance can not be used. SWFB(Stress Wave Force Balance) technique is utilized in a shock tunnel to get the thrust. As an example, a model force balance has been calculated its strain against impulse force by using FEM(Finite Element Method). A transfer function between the impulse force and strain has been obtained by the way of de-convolution.
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Papers by Sangwook Jin