Carbonaceous Deposits in a Fuel-Film-Cooled Rocket Combustor: Heat Flux Measurements

Abstract

Carbonaceous deposits can reduce heat flux in fuel-film-cooled kerosene rocket engines, but the deposition process at rocket conditions is poorly understood. Heat flux was measured in a 4.8 MPa (700 psia) fuel-film-cooled kerosene–hydrogen peroxide axisymmetric rocket combustor using 50 null point calorimeters and the Gauss–Newton algorithm with a constant Jacobian matrix. Carbon deposition caused a reduction in heat flux at axial positions furthest from the fuel-film injector, where deposits were later measured as thickest. Heat flux was reduced by a smaller amount in low-thermal-conductivity chamber liners when compared with high-thermal-conductivity copper liners. The roughness of the chamber-liner surface had little effect on quasi-steady-state heat flux but may have affected heat flux and carbon deposition during startup transients.