Coupling characteristics of combustion-gas flows generated by two energetic materials in base bleed unit under rapid depressurization

Ma, Longze; Yu, Yonggang

doi:10.1016/j.applthermaleng.2018.11.071

Cited by 16 publications

(7 citation statements)

References 15 publications

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“…In this study, the chemical dynamics mechanism of the igniter combustion-gas is from the studies by Deyong et al 39 and Ma et al, 38 and consists of three reactions as shown in Table 1 with the Arrhenius parameters. Therefore, according to the Arrhenius law, the forward rate constant of reaction r, k f,r , is expressed as:…”

Section: Chemical Kinetic Modelmentioning

confidence: 99%

“…">At the computational initial time, when the projectile moves from the muzzle to the ambient air, the AP/HTPB propellant in the BBU is assumed to extinguish, according to Xue et al 11 The pyrotechnic composition in the igniter is still in the combustion state, 38 generating Mg vapor and C 2 F 4 gas as the initial reactant of the gas phase in the unit. The chemical reactions between the igniter combustion gas (Mg vapor and C 2 F 4 gas) are considered.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…The pyrotechnic composition in the igniter is still in the combustion state, 38 generating Mg vapor and C 2 F 4 gas as the initial reactant of the gas phase in the unit.…”

Section: Mathematical Modelmentioning

confidence: 99%

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Investigation of thermal performance in dual‐fuel units

Xue

2022

Energy Science & Engineering

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Numerical studies were carried out to investigate the thermal performance of the muzzle flow with strong shock discontinuities and gas-gas heat transfer mechanism in the base bleed unit (BBU) of an aerodynamic vehicle under the combined effects of muzzle flow and depressurization process. The process was modeled using the Navier-Stokes equations with chemical kinetics and interior ballistic equations. The results show that the muzzle phenomena with large temperature gradients and different wave structures appear after the supersonic vehicle enters into the free-flight stage. The BBU also experiences a strong depressurization process with the release of high-temperature propellant gas at 2200 K. However, the igniter combustion gas at a higher temperature of 3050 K in the BBU develops downstream and upstream repeatedly under the combined effects of the base wave and depressurization process, which makes the energy conversion process in the unit more complicated. With the projectile leaving the control of the muzzle flow, the BBU is full of the igniter combustion gas and the energy in the unit is uniformly distributed gradually. The high-temperature area, at approximately 2750 K, propagates downstream along the axial and radial directions simultaneously until it finally dominates the entire unit. The maximum temperature of the combustion gas acting on the propellant surface is always 2740 K and the maximum heat flux remains approximately 1250 W/cm 2 at later periods.

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Section: Chemical Kinetic Modelmentioning

confidence: 99%

Section: Mathematical Modelmentioning

confidence: 99%

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Investigation of thermal performance in dual‐fuel units

Xue

2022

Energy Science & Engineering

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“…The set of flow visualization experiments by Dutton et al [16,[19][20][21][22] provided good understanding of base flow features with central base bleed. Recent studies on base bleed focused on finer details of base bleed operation such as muzzle exit transients [23][24][25], fracture mechanisms of base bleed grain [26,27], post-combustion of base bleed unit [28], impact of projectile spin [29], and implementing advanced numerical simulation techniques [30].…”

Section: Introductionmentioning

confidence: 99%

Live Firing and 3D Numerical Investigation of Base Bleed Exit Configuration Impact on Projectile Drag

Aziz

Ibrahim

Riad

et al. 2022

AiMT

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Base bleed, in which gases are discharged at the base of projectile, is confirmed to be an effective drag reduction technique. Itis believed that the design of base exit can impact the pattern of gas bleeding and, hence, the level of drag reduction. The present study is aimed to address this dependence that was not clarified in previous studies by examining the reduction in drag acting on a projectile with two different base bleed exit configurations. The first configuration includes a central circular orifice while the other is modified to include a smaller central circular orifice and four annular slots with equivalent total area. Numerical simulations on 3‑D computational domain have been conducted to estimate drag and to explore the base flowfield for each configuration. The computational results at different Mach numbers have been compared with the mean drag based on range shooting for projectiles with both base configurations. In addition, different simulations have been performed to predict the real pattern of bleeding through the modified configuration based on the comparison with firing data at different Mach numbers.

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“…During the depressurization process, the fuel-rich gas jet of the BBP contacts the inflow resulting in a post-combustion, which has a significant impact on the structure and thermodynamic characteristics of the wake flow field [24]. Ye [25] and Ma [26] analyzed the coupled combustion process of AP/HTPB propellant and ignition jet, and the wake chemical non-equilibrium flow field was obtained under transient depressurization.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of the Reacting Flow for the Base‐Bleed Projectile under Dual Stress

Zhou

et al. 2021

Propellants Explo Pyrotec

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While the base‐bleed projectile (BBP) is ejected from the muzzle, high‐speed rotation and rapid depressurization in the combustion chamber bring much initial disturbance to the BBP. In order to research the effect of propellant gas on the drag reduction performance for the BBP, a chemical non‐equilibrium flow model is established under the dual environmental stress of high‐speed rotation and rapid depressurization. This numerical model is coupled with a H2‐CO reaction mechanism and propellant burning rate model. Detailed numerical results of flow patterns, heat energy addition, and mass addition for various rotation speeds are discussed. The results show that the supersonic under‐expanded jet gradually transforms into a subsonic jet, and a low‐pressure recirculation zone appears at the wake of BBP. Moreover, the tangential velocity in the combustion chamber presents a typical distribution of the Rankie combined vortex. The high‐pressure jet rapidly expands to the outside low‐pressure environment, and the pressure in the combustion chamber (pc) drops sharply. After 1.15 ms, the outside gas flows back into the combustion chamber, and the rotation increases the fluctuation intensity of the inter flow field. pc reaches 0.718 p0 and remains stable after 4.0 ms. The rotation of BBP increases the pressure and Mach number near the nozzle at 5.0 ms.

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Coupling characteristics of combustion-gas flows generated by two energetic materials in base bleed unit under rapid depressurization

Cited by 16 publications

References 15 publications

Investigation of thermal performance in dual‐fuel units

Investigation of thermal performance in dual‐fuel units

Live Firing and 3D Numerical Investigation of Base Bleed Exit Configuration Impact on Projectile Drag

Characteristics of the Reacting Flow for the Base‐Bleed Projectile under Dual Stress

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