High Porosity Ceramic Matrix Composite for Cooling and Drag Reduction

Historically, the porosity associated with ceramic matrix composite structures has been viewed as a detriment for many missile applications. The standard practice is to perform several treatment/retreatment processes to reduce the porosity to an acceptable level while increasing the strength of the structure. The processing methods inherent to the production of many composite materials may provide an underexplored benefit with respect to vehicle drag reduction and engine cooling for hypersonic vehicles. Several research studies have been performed using plates with slots and holes. Depending on the mass flux rate of the cooling gas, heat transfer results incorporating staggered arrays of holes have been shown to become potentially worse than those measure without cooling. Slotted coolant injection has been shown to minimize/remove the vortex development there by reducing the mixing and localized heating phenomenon. One of the benefits to be quantified is the achieved uniformity of the composite matrix ceramic porosity. The intent is to demonstrate that the closely spaced openings associated with the composite structure emulates or more closely resembles the injection results observed with slotted coolant injection.