Water injection for rapid cooling of a flow of rocket exhaust gases

Jiang

et al. 2023

J. Phys.: Conf. Ser.

The high-temperature gas generated by the missile launch will cause serious ablation to the launcher. In order to study the thermal protection of the launch device, a scheme of arranging vertical upward water spray pipes in the deflector is proposed, which realizes the thermal protection of the launcher by the vaporization and heat absorption principle of liquid water and the impact effect. Based on the Mixture multiphase flow model, coupled with the vaporization equation of liquid water and the component transport model, the cooling mechanism and effect of the proposed scheme are analyzed. Meanwhile, the numerical simulation of gas flow field under different water injection speed conditions is carried out, and the change law between different water injection speed and cooling effect is obtained. The results show that after the water sprayed by the pipes laid in the deflector, a water film will be formed on the surface of the deflector and the wall of the launch vehicle, which plays a role in the isolation of the high-temperature gas. The temperature of the launch device drops significantly. With the increase of water injection speed, the thickness of the water film formed on the surface of the deflector and the wall of the launch vehicle becomes larger, and the isolation effect on the gas becomes more obvious. When the water injection speed increases to 55m/s, the vaporization rate of liquid water in the direct impact area of the gas jet reaches the maximum, the heat absorption is the most at the same time, and the temperature in this area reaches the lowest level. The cooling effect of the water spray speed of 55m/s on the flow field is the best. This conclusion can provide a theoretical reference for the thermal protection design of missile launcher.

Section: Mixture Multiphase Flow Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Research on the Cooling Effect of Water Injection of the Deflector on Flame of the Vertical Launch Missile

Jiang

et al. 2023

J. Phys.: Conf. Ser.

“…For a long time, reducing the temperature and noises of the gaseous jet has become an important subject in experimental, theoretical, and numerical investigations. Geery [3] first used water injection to reduce the temperature and noises of gaseous jet. In the process of injecting water into the gaseous jet, strong energy exchange and momentum exchange occur between the liquid-water and the gaseous jet, reducing the temperature and speed of the gaseous jet, thus achieving the goals of cooling and noises reduction.…”

Section: Introductionmentioning

confidence: 99%

Studies of flow field characteristics during the impact of a gaseous jet on liquid–water column*

et al. 2019

Both experimental and numerical studies were presented on the flow field characteristics in the process of gaseous jet impinging on liquid–water column. The effects of the impinging process on the working performance of rocket engine were also analyzed. The experimental results showed that the liquid–water had better flame and smoke dissipation effect in the process of gaseous jet impinging on liquid–water column. However, the interaction between the gaseous jet and the liquid–water column resulted in two pressure oscillations with large amplitude appearing in the combustion chamber of the rocket engine with instantaneous pressure increased by 17.73% and 17.93%, respectively. To analyze the phenomena, a new computational method was proposed by coupling the governing equations of the MIXTURE model with the phase change equations of water and the combustion equation of propellant. Numerical simulations were carried out on the generation of gas, the accelerate gas flow, and the mutual interaction between gaseous jet and liquid–water column. Numerical simulations showed that a cavity would be formed in the liquid–water column when gaseous jet impinged on the liquid–water column. The development speed of the cavity increased obviously after each pressure oscillation. In the initial stage of impingement, the gaseous jet was blocked due to the inertia effect of high-density water, and a large amount of gas gathered in the area between the nozzle throat and the gas–liquid interface. The shock wave was formed in the nozzle expansion section. Under the dual action of the reverse pressure wave and the continuously ejected high-temperature gas upstream, the shock wave moved repeatedly in the nozzle expansion section, which led to the flow of gas in the combustion chamber being blocked, released, re-blocked, and re-released. This was also the main reason for the pressure oscillations in the combustion chamber.

International Journal of Nonlinear Sciences and Numerical Simulation

Numerical study of gas–liquid two-phase flow and noise characteristics for a water injection launching concentric canister launcher

Zou

Yang

Cai

et al. 2021

In view of the poor thermodynamic environment problem of the self-powered launch of land-based concentric canister launcher (CCL), the launching scheme of injecting water at the bottom of launching tube is adopted to improve the thermodynamic environment of the launching system fundamentally. The solution program for liquid water vaporization is compiled and embedded into the homogeneous gas–liquid two-phase flow model, the source phase corrections of the momentum equation and the energy equation are also performed, and then the three-dimensional gas–liquid two-phase fluid dynamics model is established for the land-based CCL; analysis shows that the improvement of the thermal environment of the 35° and 45° water injection schemes is more better among these schemes. So coupling the mixture model, vaporization program and FW–H (Ffowcs Williams Hawkings) noise model, the noise distribution law in the bottom of the launcher cube for 35 and 45 water injection angles is discussed; in the intermediate frequency range, the −45° water injection scheme is about 2–10 dB higher than the noise signal of the −30° water injection scheme. Finally, it is recommended to optimize the overall thermal environment of the CCL by using the −30° preferred water injection scheme with both cooling effect and noise control.