Burn rate (chemistry)

About: Burn rate (chemistry) is a research topic. Over the lifetime, 847 publications have been published within this topic receiving 8908 citations. The topic is also known as: Burning rate.

Development of solid rocket propellant

Abstract: This thesis presents a study on development of solid rocket propellant that was carried out at Universiti Malaysia Pahang. Rocket propellant has been identified as a component that played an important role in the development of rockets. The ejected material in rocket propulsion is due to material called propellant. Without propellant, a rocket cannot be launched. A solid rocket is a class of rocket in which the fuel, oxidizer and binder are mixed together and cast into a solid material. Objective of this thesis is to produce potassium nitrate sucrose based solid rocket propellant. Materials used to produce this propellant are potassium nitrate powder and sucrose powder. Potassium nitrate is an oxidizer in the propellant material and sucrose as a fuel in the propellant. This propellant is produce using the method of formation. This method was easy to operate and cost effective. Burning rate test was carried out at 1 atm and 7 atm pressure using a different oxidizer/fuel mass ratio. At 1 atm pressure, it was found that burning rate for the ratio of 65/35 was 2.184 mm/sec. At 7 atm, it was found that burning rate for the ratio 65/35 was 3.791 mm/sec. Propellant must be kept in a cool dry place like it in the refrigerator to prevent it become melt. From the result of this research, the burning rate test rig has been successfully designed, fabricated and tested. As a conclusion, oxidizer / fuel ratio and combustion pressure influence burning rate test.

Star Grain Regression under Spin Induced Acceleration Effect

Abstract: Spinning is used in some of solid rocket motors to increase the flight trajectory precision or for stability requirements. The angular acceleration due to the spin effect increases the burning rate of solid propellant and changes the motor performance by increasing the operating pressure and decreasing the burning time. So it is important to know the grain regression taken place in the solid propellant rocket motor in the acceleration field. In this study, we represent the grain regression analysis of two-dimensional axis-symmetric star grain configuration of the solid propellant rocket motor under spin induced acceleration effect to study how the spin affects on the internal ballistics of the solid rocket motor. Grain regression is done by two methods - geometrical approach and numerical approach. The burning rates on the propellant surface are different with its radial distance, acceleration vector angle and surface slope when the rocket is spinning. With the different burn rates on the propellant surface, the propellant surface perimeter and port area are computed by using the numerical method, and the results are compared with that of constant burn rate.

An Experimental Determination of Subatmospheric Burning Rates and Critical Diameters for AP/HTPB Propellant

Abstract: : Measurements have been made of the burning rates of two formulations of AP/HTPB propellant in the pressure range of 0.3-1 atm. The experiments were performed in a windowed strand burner modified to operate under subatmospheric pressure conditions. Burning rates of the two formulations differ by almost a factor of two and the pressure dependence of both is well described by the usual power law function. Although 6.4 mm strands of the faster formulation burned stably down to 0.3 atm, it was found that the slower formulation strands would not burn stably even at 1 atm except in larger diameters. The critical diameter for self-extinguishment was found to increase with decreasing pressure. Propellant burning rate, Vacuum, Deflagration limit.

Initiation of Chemical Reactions in Energetic Materials Using Plasmas and Arc Channels

Abstract: : Development of arc channels in propellant beds will lead to initiation of chemical reactions and possible ignition. Same initiation can take place with high-energy density plasmas generated by electrothermal plasma sources. Arc channels can be simulated via arc generators from as low as few milli-joules to several joules of energy. For electrothermal plasmas, the energy is in the range of few kilo-joules. When using electrothermal plasmas, the performance of the propellant is more governed by radiation transport and the plasma-flow-field parameters. The temperature of the propellant's bed may also play a role in the burn rates under plasma injection. In this report, a set of experiments were first conducted on the plasma-flow-field to determine the spatial and temporal distribution of the plasma temperature, pressure, number density, and velocity. The experiments revealed a decreasing plasma pressure, plasma temperature and plasma number density as plasma is leaving the capillary source and expands in air. The plasma jet velocity 2 inches from the source exit was found to be about 1300 m/s. Following characterization of the plasma-flow-field, a set of experiments were conducted on JA-2 solid propellant with controlled bed temperature. Increased burn rates were observed with increased bed. A model for the burn rate is proposed, which includes the bed temperature and has the BR = A P(sup a) (T/T(sub ambient))(sup b).

Performance of Nitramine Propellants with Different Phases of HMX

Abstract: In order to study the effects of phases of HMX on the nitramine propellants,the combustion performance and mechanical properties of nitramine propellants containing α-HMX and β-HMX were tested by closed combustion bomb and mechanical properties tester.Results show that the propellant with α-HMX is easy to be ignited and its gas generation brisance and combustion rate is lower than that with β-HMX,and the burning rate pressure exponent of the propellant with α-HMX is 0.1 higher than that with β-HMX and mechanical properties of the propellant with α-HMX is worse.In addition,when loading density is 0.12 g·cm-3,the two burning rate pressure exponents are larger than 1,and when loading density is 0.20 g·cm-3,the two burning rate pressure exponents reach the level of less than 1.