Annular cavitator with water injection is one of the key parts of the long-range supercavitating vehiclepowered by water ramjet. In this paper, hydrodynamic properties of annular cavitator are studiednumerically. The standard k ~ ε turbulence model is coupled with the Reynolds Averaged Navier-Stokes(RANS) equations to model the natural supercavitation process. The multiphase flow is considered asa mixture of varying density and modeled by the mass exchange equations. To fully understand this process,numerical simulations were performed for different annular cavitators. Computational Fluid Dynamics(CFD) results, including the pressure distribution and forces acting on the cavitator surface, mass flowand pressure loss of water injection, various supercavity sizes, were obtained and analyzed. The pressuredistribution on the cavitator surface was significantly changed which resulted in 4 ~ 6% increase of thetotal drag of the vehicle. The results show that the mass flow and velocity of the injection water is mainlydependent on the tube size, while the total pressure loss of the water injection is mostly related to the outletpressure. Supercavity generated by annular cavitator is smaller than that of the discal one. Based on thecorrelation analysis of the supercavity size and other factors, it could be concluded that the contraction ofthe cavity size is mainly caused by the diffluent mass flow of the water injection.
428XL Sercel's a whole new concept design of a reliable, low power consumption, high precision, with channel capacity, compatibility strong earthquake Instruments data acquisition system. In large telemetry seismograph systems need to import most of Instrument Science and Electrical Engineering of Jilin University breakthrough design constraints of conventional seismographs designed a lightweight, highly integrated, easy to operate telemetry seismic system-GEIST438. This article describes the characteristics of the two systems, with a focus on a variety of ground electronic equipment technical performance of the two systems were compared, Last the GEIST438 how ultra ten thousand telemetry seismograph system were discussed.
The saturation-free and directionless cross-linking and interpenetration processes between La 3+ and [(H 2 PO 4 )2Al(HPO 4 )]-plasma in La−Al phosphate by mixing Al(OH) 3 , CrO 3 , and H 2 O 2 dissolved in H 3 PO 4 and La 2 O 3 as a curing accelerator, as well as the thermal stability of the La−Al phosphate bulk materials and the evolutions of the phase composition and morphology at different temperatures were studied using thermogravimetric/differential scanning calorimetry under different temperatures in a muffle furnace. The La−Al phosphates showed good thermal stability, and the thermal weight loss rate of the materials decreased from 18% before heat treatment to ∼2% after heat treatment. In addition, the La−Al phosphate bulk material showed excellent resistance to ablation when subjected to ablation by an oxyacetylene flame at 2000 °C for 30 s. It evolved into a dense LaPO 4 and AlPO 4 high-temperature phase layer on the sample surface, which prevented further ablation damage to the sample and significantly improved the temperature resistance of the La−Al phosphate bulk material.
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