Pressure-Time Study of Slow Burning Rate Ap/HTPB Based Composite Propellant by Using Closed Vessel Test (CVT)

Amir Mukhtar,Hizba Waheed,Habib Nasir

doi:10.4028/www.scientific.net/kem.778.268

Amir Mukhtar, Hizba Waheed + Show 1 more

Open Access

https://doi.org/10.4028/www.scientific.net/kem.778.268

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Abstract

The Closed vessel (CV) is an equipment used to study the ballistic parameters by recording burning time history, pressure buildup during the process and vivacity of the propellants. It is an apparatus which consists of strong pressure vessel, piezo-electric pressure transducers, sensors and dedicated software. To save time and resources this method is employed instead of dynamic firing while doing research and development of propellants. A measured amount of propellant charge is loaded in the vessel and fired remotely. Ignition is provided by the filament which ignites the black powder charge. In this study, we have used Closed Vessel Tests (CVT) for the first time for recording the ballistic parameters of slow burning composite rocket propellant. We developed a set of composite solid propellant samples containing a mixture of bimodal Ammonium Perchlorate (AP) as an oxidizer, Hydroxy-terminated Polybutadiene (HTPB) as a binder as well as fuel, Dioctyl Sebacate (DOS) as plasticizer, 1-(2-methyl) Aziridinyl Phosphine Oxide (MAPO) as bonding agent and Toluene Diisocyanate (TDI) as curator. Samples were developed by changing the solid loading percentage of bimodal AP particles. By increasing the percentage of AP, the oxidizer-fuel ratio (O/F) increases which effects the ballistic parameters. It is observed that maximum pressure and vivacity increases with increase in solid filler in the propellants. As quantity of AP increases, rate of rise of pressure also increases. CVT firing of each sample was done three times to obtain average burning time and pressure buildup history to evaluate the effect of oxidizer loadings on ballistic parameters of the composite propellant.

Highlights

Composite solid propellants with very high rate of burning produce a higher impulse by releasing combustion products in very short time enabling missiles to fly at high velocity
Composite propellant is mainly composed of Hydroxy-terminated Polybutadiene (HTPB) binder, Ammonium Perchlorate (AP) as oxidizer and Al powder as metal fuel [4]
All composite propellants investigated in this paper are composed of HTPB (15-19%) binder cum fuel, AP (75-84%) as oxidizer and Al powder (1%) as burning stabilizer and opacifier

Summary

Introduction

Composite solid propellants with very high rate of burning produce a higher impulse by releasing combustion products in very short time enabling missiles to fly at high velocity. The burning rate is the most important property affecting the ballistic performance of composite propellant motors and most contributing ingredient is the oxidizer. It increases with increase in the AP content in the composition which ranges from 70 to 90 % by mass [8, 15]. All the samples were of 100 grams mass and prepared in Porcelain dishes by hand mixing with glass stirring rods This final propellant material was cast into specific molds and was cured at 60 °C for 78 hours. According to the theory of constant volume, the propellant charge as per the loading density and required quantity of ignition powder of all the four is as shown in the Table 1

Result and Discussion

Findings

A-1 A-2 A-3 A-4

Conclusions