Optimization of 2-stage gas gun for fusion refueling pellet injection with consideration of real effects

Analytic expression of pellet acceleration by constant base pressure with consideration of gas-wall friction, heat transfer and viscous dissipation that important for high speed injection is obtained. The process of compression stage is formulated by a set of governing equations and can be numerically integrated. Excellent confirmation with experiments is obtained and the ways to optimum match the compression stage with the launch stage are suggested.

Investigation of Vaporized Kerosene Injection in a Supersonic Model Combustor

Characteristics of vaporized aviation kerosene injection in a supersonic model combustor were preliminarily investigated. The electrically storage type heater has a volume capacity of heating kerosene of 0.8 kg up to 670 K at a pressure of 5.5 Mpa. The temperature to cause pressurized kerosene jet being fully vaporized in Quiescent atmosphere was found to be 550 K at 4 Mpa however the pressurized hot kerosene remains in liquid state within the tube. The correspondent jet spray in Mach 2.5 vitiated air cross-flow were visualized by using stop schlieren photograph.It was found the penetration depth of the hot pressurized kerosene jet is approximately same with the temperature varied from 290 K to 550 k. at pressure of 4 Mpa. This results showed that the atomization process of hot kerosene jet spray in supersonic combustor could be bypassed and directly transferred to be gas state at temperature 550 K and pressure of 4 Mpa.

Performance of a Supersonic Model Combustor using Vaporized Kerosene Injection

Characteristics of supersonic combustion by injecting kerosene vapor into a Mach 2.5 crossflow at various preheat temperatures and pressures were investigated experimentally. A two-stage heating system has been designed and tested, which can prepare heated kerosene of 0.8 kg up to 820 K at pressure of 5.5 Mpa with minimum/negligible fuel coking. In order to simulate the thermophysical properties of kerosene over a wide range of thermodynamic conditions, a three-component surrogate that matches the compound class of the parent fuel was employed. The flow rate of kerosene vapor was calibrated using a sonic nozzle. Computed flow rates using the surrogate fuel are in agreement with the experimental data. Kerosene jets at various preheat temperatures injecting into both quiescent environment and Mach 2.5 crossflow were visualized. It was found that at injection pressure of 4 Mpa and preheat temperature of 550 K the kerosene jet was completely in vapor phase, while keeping almost the same penetration depth as compared to the liquid kerosene injection. Supersonic combustion tests were also carried out to compare the combustor performance for the cases of vaporized kerosene injection, liquid kerosene injection, and effervescent atomization with hydrogen barbotage, under the similar stagnation conditions. Experimental results demonstrated that the use of vaporized kerosene injection leads to better combustor performance. Further parametric study on vaporized kerosene injection in a supersonic model combustor is needed to assess the combustion efficiency as well as to identify the controlling mechanism for the overall combustion enhancement.

Investigation of Vaporized Kerosene Injection and Combustion in a Supersonic Model Combustor

Injection and combustion of vaporized kerosene was experimentally investigated in a Mach 2.5 model combustor at various fuel temperatures and injection pressures. A unique kerosene heating and delivery system, which can prepare heated kerosene up to 820 K at a pressure of 5.5 MPa with negligible fuel coking, was developed. A three-species surrogate was employed to simulate the thermophysical properties of kerosene. The calculated thermophysical properties of surrogate provided insight into the fuel flow control in experiments. Kerosene jet structures at various preheat temperatures injecting into both quiescent environment and a Mach 2.5 crossflow were characterized. It was shown that the use ofvaporized kerosene injection holds the potential of enhancing fuel-air mixing and promoting overall burning. Supersonic combustion tests further confirmed the preceding conjecture by comparing the combustor performances of supercritical kerosene with those of liquid kerosene and effervescent atomization with hydrogen barbotage. Under the similar flow conditions and overall kerosene equivalence ratios, experimental results illustrated that the combustion efficiency of supercritical kerosene increased approximately 10-15% over that of liquid kerosene, which was comparable to that of effervescent atomization.