水下无人系统学报 (Jun 2024)
Development Characteristics of Underwater Detonation Gas Jets in Confined Space
Abstract
To explore the development characteristics of gas jets generated by pulsed detonation water ramjet engines working underwater in water deflectors, numerical simulations and experimental validations were conducted on underwater detonation gas jets generated by detonation tube within a cylindrical confined space by utilizing the detonation of combustible gases to generate pulsating bubbles in the underwater confined space. A flow field model of a single gas jet in an underwater confined space was established based on the Reynolds-averaged equations, the k-ε two-equation model, and the gas-liquid interface tracking method of the volume of fluid(VOF) coupled with the phase transportation equation. The Compressible Inter Foam solver in OpenFOAM was employed for numerically solving pulsed detonation gas jets in the confined space. The results show that the influence of confined space on the leading shock wave of underwater detonation is slight, and the amplitude of the leading shock wave changes insignificantly compared to that in free underwater space. However, the pressure disturbance caused by the detonation gas jet significantly increases, and its duration is prolonged. Additionally, it leads to a noticeable increase in pressure within the confined space compared to that outside the confined space. The pulsation period of bubbles in the confined space is extended to approximately 60 ms, and the radial dimension of the confined space has little effect on the fluctuation period of the bubbles. Therefore, it can be seen that confined space can increase the near-field pressure at the outlet of the underwater detonation tube and extend the action time of the gas jet. The research results are of important guiding significance for the study of thrust performance improvement methods for pulsed detonation water ramjet engines.
Keywords
