Optically Resolved Fuel Regression of a Clear PMMA Hybrid Rocket Motor

Pseudo-Two-Dimensional Modeling and Validation of a Hybrid Rocket Combustion Chamber

“…This code has also been employed before for a HRE problem [10,23,24], providing in general, good estimations about the temperature and the fuel regression rate values in the combustion chamber. In particular, combustion conditions are retrieved through a constant temperature-pressure problem, where the inputs are the molecular formulas of the reactants (oxidizer and pyrolyzed fuel) and their corresponding temperature, pressure and mass fractions.…”

“…( 6) and ( 7), the integral equations of mass and axial quantity of momentum in the boundary layer result in Eqs. ( 9) and (10), respectively. The radial mass flux term at the BL edge (ρ e v δ ) appearing in the integral continuity equation of the core flow [Eq.…”

“…( 29) a and n are constant preexponential and exponential coefficients, respectively. Both of them result from a polynomial adjustment coming from empirical data, generally leading to a coefficient of determination, R 2 , that can vary in a wide range (approximately from 0.43 to 0.99 [10,[51][52][53]). This power law is most employed in numerical models to describe HRE fuel pyrolysis in a simple and direct way.…”

“…Moreover, from literature data, the local fuel consumption is found to be very dependent on the entrance characteristics to the fuel channel, which influence then, the aerodynamics in the combustion chamber and hence, the thermal exchanges with the fuel. These characteristics are defined by the injection type [53,70,71] and the precombustion chamber features such as its dimensions [10]. The formulation presented in this paper has been developed for an axial injection type.…”

“…The final aim in the exploitation of such tools results in the implementation of optimization algorithms enabling to obtain the best HRE configuration that accomplishes the mission requirements (specified ∆V and total spacecraft mass, for example) while enhancing some engine characteristics like the payload mass, the thrust level, the nozzle expansion ratio, etc. Several authors [8][9][10] have already developed and validated codes like these, providing HRE designs that prove to be a better choice (implying smaller economical costs and better performances) compared with other existing bipropellant propulsion system designs. These tools implement 0-D models or very simplified 1-D models to describe the internal chamber physics, with the use of semiempirical expressions (through fit coefficients) to characterize the fuel pyrolysis, such as the one proposed by Marxman [11].…”