Erosive Burning Research Articles

Application of the Saderholm erosive burning model to nozzleless solid propellant rocket motors

This paper demonstrates the ability of the Saderholm erosive burning model, when coupled with the Air Force Rocket Propulsion Laboratory Nozzleless Rocket Motor Internal Ballistics Computer Program, to predict the ballistic performance of six nozzleless rocket motors of three designs loaded with three nonaluminized HTPB propellants. The paper describes the Saderholm erosive burning model, the six nozzleless test motors, and the ballistics prediction methodology. The results for instantaneous and total ballistic parameters show that the Saderholm erosive burning model as developed for nozzled rocket motors predicts the ballistic performance of nozzleless rocket motors as well as or better than the Erosive Model 1 developed specifically for nozzleless rocket motors and built into the AFRPL computer program.

A comprehensive erosive-burning model for double-base propellants in strong turbulent shear flow

A comprehensive aerothermochemical model of erosive burning of double-base propellants has been developed. The present analysis includes detailed modeling of the combustion process, taking into account both chemical kinetics and diffusion effects in the gas phase. Different reactions simulating the fizz zone and the final flame zone (including dark and luminous zones) are considered in the gas phase. The instantaneous governing partial differential equations are Favre averaged to take into account variable density effects. The turbulence modeling consists of a two-equation ( k-ϵ) turbulence closure model for the final Favre-averaged conservation equations. The set of governing equations is solved numerically. Predicted results compare well with experimental data of Burick and Osborn for a noncatalytic double-base propellant. Predicted temperature profiles in the boundary layer correctly depict the characteristics of double-base propellant combustion. The main mechanisms for augmentation of the burning rate is the increase in heat feedback caused by turbulence-enhanced reactions and transport properties in the fizz zone.

Comment on "Theoretical Prediction of Erosive Burning Characteristics of Solid Rocket Propellant"

Comment on "Theoretical Prediction of Erosive Burning Characteristics of Solid Rocket Propellant"

Reply to comments of Rastogi, singh, and Rao on erosive burning models

Reply to comments of Rastogi, singh, and Rao on erosive burning models

Comment on "Turbulent Flow Analysis of Erosive Burning of Cylindrical Composite Solid Propellants"

Comment on "Turbulent Flow Analysis of Erosive Burning of Cylindrical Composite Solid Propellants"

Comment on "Turbulent Flow Analysis of Erosive Burning of Cylindrical Composite Solid Propellants"

Comment on "Turbulent Flow Analysis of Erosive Burning of Cylindrical Composite Solid Propellants"

Erosive Burning of Composite Solid Propellants: Mechanism, Correlation, and Grain Design Applications

With increasing interest evidenced in the developrrient of nozzleless and high-performance solid rocket motors, an understanding of Ifie errrsivz-bsrning charwrter:;iics of sollid propellants in high-velocity cross flows is important in establishment of grain design procedures. A theo~etical model based on a turbulent reacting boundary-layer analysis, validated with experimentnl data, was used to conduct parametric studies under broad ranges of Mach number, pressure, surface roughness, pressure gradient, port diameter, and propellant initial temperature. Using nonlinear regression analysis, an erosive-burning rate correlation was developed in terms of the cited parameters. The results for two motor grain contours were used to demonstrate the applicability of this correlation to grain design.

Turbulent Flow Analysis of Erosive Burning of Cylindrical Composite Solid Propellants

An axisymmetric turbulent boundary layer was analyzed in order to investigate erosive burning in composite solid-propellant rocket motors. It was found that there is a strong interaction between the core flow acceleration and turbulence level in the boundary layer. The increase of turbulence near the surface of the propellant plays an important role in the erosive burning mechanism. Reducing the port diameter makes a rocket motor more sensitive to erosive burning. When the port diameter is uniform, the erosive burning rate increases toward the aft end of the rocket motor. This trend is less pronounced or even reversed when the port diameter is divergent.

Erosive burning of condensed materials in an acoustic field

Erosive burning of condensed materials in an acoustic field

Experimental and theoretical study of the effects of pressure and crossflow velocity on composite propellant burning rate

A model for prediction of burning rates of composite (ammonium perchlorate oxidizer) propellants has been developed. In addition, an experimental device for measuring effects of crossflow on burning rate has been used to characterize eight propellants with systematicall, varied formulation parameters. Model predictions of no-crossflow burning rate-pressure behavior agree very well with data, while agreement between erosive burning predictions and data is generally good. The dominant factor influencing composite propellant burning rate sensitivity to crossflow is the base (no-crossflow) burning rate (lower base rate leading to increased sensitivity) with other factors having at most second order effects outside their influence on base rate. Three formulations with widely variant compositional and ingredient particle size parameters, but nearly identical base burning characteristics, exhibited very similar crossflow behavior.

Aerothermochemical Analysis of Erosive Burning in a Laboratory Solid-Rocket Motor

An analysis of steady-state combustion and flow phenomena in a two-dimensional, laboratory-type solidpropellant motor is presented with emphasis on the condition of erosive burning. The problem is treated as a confined, reacting turbulent shear-flow using a second-order turbulence closure model. Low Reynolds number and propellant surface roughness effects are accounted for. Comparison of calculated results with cold flow experimental data confirms that development of the mean velocity profile is initially well described by laminar, 'inviscid theory. However, due to the rapid development of turbulence within the simulated grain-port, transition to a turbulent velocity profile is predicted to occur at center port Reynolds numbers greater than those obtained in the considered experiments. Transition of the velocity profile is theoretically found to occur prior to the onset of erosive burning in real motor environments. Comparisons of calculated results with measured static pressure distributions have been made for a composite-propellant slab motor. Good agreement with static pressure data is obtained for propellant roughness heights which are approximately 10 % of the larger AP crystal diameters, with surface roughness significantly affecting erosive burning. Theoretical comparison with the Lenoir-Robillard model also indicates that the present model predicts a much more rapid decrease in erosive burning as the port hydraulic radius is increased.

Measurements and Model Validation for Composite Propellants Burning under Cross Flow of Gases

Erosive burning rates of three types of ammonium perchlorate-based composite propellant formulations were measured by using the high-speed motion picture method. Experiments were conducted in a test rig designed to develop a well-defined, turbulent boundary layer with a distinct leading edge by the flow of combustion gases over two-dimensional propellant samples. Erosive burning rate correlations which relate the burning rate to freestream velocity and pressure were developed. The comparison of experimental data and theoretical results obtained from the erosive burning model, based upon the turblilent boundary-layer approach developed by the authors, showed a close agreement.

Erosive Burning Study of Composite Solid Propellants by Turbulent Boundary-Layer Approach

Erosive burning of composite solid propellants is investigated by analyzing a steady, two-dimensional, chemically reacting, turbulent boundary layer over a propellant surface. Predicted erosive burning rates agree closely with experimental data. The erosive burning rate augmentation is found to be caused by the increase in heat feedback introduced by the increase in transport coefficients, and the turbulence enhanced mixing and reaction of the oxidizer and fuel gases. The increase in freestream gas velocity brings the location of the peak turbulence intensity and the heat release zone closer to the propellant surface, thereby increasing the burning rate of a propellant.

Reacting Turbulent Boundary-Layer Approach to Solid Propellant Erosive Burning

Abstract : A theoretical analysis of the erosive burning of solid propellants is presented using a reacting turbulent boundary layer approach. The turbulent field is modeled using the second-order closure technique and a single-step gas-phase reaction is assumed for the combustion of a homogeneous propellant. The calculated results agree with the generally observed erosive burning trends of threshold velocity, nonlinear recession-ratio velocity dependence, pressure dependence, and normal burning rate sensitivity. For constant external velocity boundary layers, the results show a decrease in burning rate along the propellant surface, which also has been observed experimentally. Examination of calculated profiles of temperature and turbulent correlations in the boundary layer reveals that erosive burning is predominantly caused by flame zone broadening due to the diffusive effects of turbulence. (Author)

A Comprehensive Theory of Erosive Burning in Solid Rocket Propeilants

The theory of erosive burning has been constructed front first principles using turbulent boundary layer concepts. It is shown that the problem constitutes one of solution of flame propagation equation for turbulent flow. The final approximate solution for the case of single step overall kinetics reveals the combined effects of fluid mechanics and chemical kinetics. The results obtained from this theory are compared with earlier experimental results. The dependence of erosive burning characteristics on various parameters has been elucidated.

A Model of Erosive Burning of Composite Propellants

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.

Theoretical Prediction of Erosive Burning Characteristics of Solid Propellant

HE aim of this paper is to provide the designer of modern solid propellant motors with a successful theoretical basis for predicting the erosive burning effects that are already in the designing phase. This is done by means of modified Lenoir-Robillard formulas and theoretically determined unkown parameters. In up-to-date practice, a great deal of experimental investigation had to be done to define those constants. The application range of this theory has been extended on plateaunized propellants with negative erosion effects. The only experimental constants required by this method are the linear burning rate law and initial temperature sensitivity.

Simulative Study on the Erosive Burning of Solid Rocket Motors

A simulative study is presented to clarify the characteristics of the flowfield in the grain port of a solid rocket motor under erosive burning conditions. The experiments are performed by using channels with porous walls and air flow at ambient temperature. It is shown that the boundary layer along the port develops rapidly similarly to pipe flow, which differs from Green's prediction. An empirical relation, similar to LenoirRobillard's semiempirical relation is obtained by correlating turbulence intensity with velocities and geometrical parameters of the channel. Thus, it is implied that an intimate relation exists between turbulence intensity and erosive burning.

Comment on: A modification of the composite propellant erosive burning model of lenoir and robillard

Commenting on a paper by King, Glick uses King's numerical estimates and an assumption to show that erosive burning models based on additive heat fluxes are invalid and that erosive burning in composite propellants probably stems from wall shear-induced interactions in the condensed phase melt. In his response. King finds fault with Glick's assumption of a 1-dimensional homogeneous picture of solid propellant combustion. While King declines to defend the model of erosive burning, he disagrees with Glick's argument against summing of heat fluxes. (DDA)

A modification of the composite propellant erosive burning model of lenoir and robillard

The Lenoir and Robillard model for the erosive burning of composite propellants is shown to suffer from use of an incorrect additivity law for coupling of the effects of heat feedback from the propellant flame and feedback from the core gas. A revised expression, employing a physically realistic additivity concept is derived and shown to fit data from an independent source at least as well as the original expression.