Study of Initial Pressure Rise in Multi Grain Solid Propellant Rocket Motor

In order to study the effects of confining pressure and strain rate on the mechanical properties of the Nitrate Ester Plasticized Polyether (NEPE) propellant, compressive tests were conducted under various confining pressure conditions and strain rates using a new‐designed active gas confining pressure testing machine. The stress‐strain curves and mechanical properties of the NEPE propellant under varying confining pressure conditions and strain rates were obtained. The results show that the compressive mechanical properties of the NEPE propellant are remarkably influenced by the confining pressure and strain rate. The compressive strength under confining pressure is obviously larger than those without applied confining pressure. With the coupled effects of the confining pressure and strain rate, the compressive strength under 5.4 MPa and 6.67×10−2 s−1 is 2.17 times of its value at room condition and 6.67×10−4 s−1. Then, based on previous tensile results, the quantified comparisons of tensile and compressive mechanical properties under different experimental conditions were presented. Finally, a nonlinear constitutive model with damage was constructed to model the effect of pressure. The statistical damage model parameters were defined as ExpDec1 function of pressure P. The calibrated model can accurately predict the mechanical behaviour of the NEPE propellant under different confining pressure conditions and strain rates.

Section: Experimental Methodologymentioning

confidence: 99%

Experimental Investigation and Modeling the Compressive Behavior of NEPE Propellant under Confining Pressure

Chen

Hou

et al. 2021

“…All components are made from mild steel of IS-2062 grade. Various components of the rocket motor are shown in Figure 5 [26].…”

Section: Rocket Motor Componentsmentioning

confidence: 99%

Study of Maximum Pressure Rise with Erosive Burning in Multi‐Grain Tubular Solid Propellant

Ropia

Upadhyay

Kalal

et al. 2020

Self Cite

In the present study, the mathematical prediction with the Paul‐Mukunda model is carried out for maximum pressure rise with erosive burning in multi‐grain solid rocket propellant. For this study, a cluster of 7 tubular solid double‐base propellant grains is selected. The erosive burning model has given a fair idea of the maximum pressure rise in rocket motors. The maximum pressure rise due to the erosive burning effect is quite a lot higher than without the erosive burning effect. The erosive burning model helps in studying maximum pressure rise for various configurations of propellant grains. It is found that lowering the outer diameter (OD) of propellant grains is giving low maximum pressure in rocket motor in comparison to increasing the inner diameter (ID) of propellant grains. Ap/At (port area to throat area) ratio is maintained same for both the cases. Although in both the cases predicted maximum flow velocity of propellant gases is almost same. It shows that keeping the same Ap/At ratio and erosive burning effect, the maximum pressure is reduced significantly by lowering OD of propellant grains than increasing the ID of the propellant grains in rocket motor. This study will help to reduce the maximum pressure rise in rocket motors for safe working.

“…In recent years, studies on the ignition process of solid rocket motors have achieved good results. Previous research content has included the ignition process characteristics of solid rocket motors with endburning grains [3,4], tube grains [5-9, 10, 11, 12, 13-16], multigrains [17][18][19], wing grains [13,20,21], and the influence of the opening pressure of the cover [3], the quality of the ignition powder [22,23,24], the initial temperature of the propellant [25] and other factors on the ignition process of the solid rocket motor. In terms of experiments, Kuo et al studied the flame propagation characteristics in the wing slot region of a small-scale rocket engine with a noninvasive optical diagnostic method [26].…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of the effect of multiple factors on the ignition process of a solid rocket motor

Li,

Liu,

Zhang

et al. 2024

With the continuous development of manned space technology, higher requirements have been proposed for solid rocket motors. The ignition process of solid rocket motors affects the reliability, stability and safety of their operation. The ignition powder, cover opening pressure and grain length‐diameter ratio are the main factors affecting the ignition process. Therefore, the influence of different factors on the ignition process of solid rocket motors is studied with numerical simulations. Based on the finite volume method, the ignition process of a solid rocket motor is modelled and experimentally verified. Then, the pressure and temperature distribution characteristics during the ignition delay, flame propagation and gas filling times are analysed. Finally, the effects of different ignition powders, cover opening pressures and length‐diameter ratios on the ignition process are compared and analysed. The results show that the model has high prediction accuracy. When the ignition powder is 6 g, the maximum combustion temperature of solid rocket motor increases from 2590 K to 2620 K between 0.1 ms and 0.44 ms. Between 0.44 ms and 3.18 ms, intermittent flame propagation and pressure oscillations occur. In the gas filling time, the flow field gradually stabilizes. Increasing the ignition powder mass is beneficial to the ignition process, but the disadvantages of pressure oscillations should be considered. Increasing the cover opening pressure enhances the ignition process, while increasing the length‐diameter ratio increases the ignition pressure building time. The study results provide technical support for the structural design of solid rocket motors.