Investigation into Wedge Turbulators and Aspect Ratio in Rocket Engine Cooling Channels

With reusability being a novel design parameter for liquid rocket engines (LRE), the need to lower internal wall temperatures for an increased engine longevity is a desired outcome. One of the mechanisms that has been effectively implemented is the use of high aspect ratio cooling channels (HARCC) to promote fin-like effects from internal cooling channel sidewalls. In the gas turbine industry, the use of wedge turbulators has gained recognition for its heat augmentation properties with relatively low pressure drop penalty. In an ideal case, LRE’s could adopt the wedge turbulator cooling technique to enhance the benefits of HARCC with minimal penalty; however, the relationship between these two cooling schemes in a LRE environment is relatively unknown. A conjugate heat transfer analysis is performed on wedge turbulator features on various channels of differing aspect ratios. The boundary and initial conditions of the validation channel geometry is taken from a simulated 1 MN Vulcain engine high-aspect ratio cooling channel environment. After smooth walled channels are validated from a previous study, backward facing wedge turbulators are introduced into the channel in order to observe and analyze heat augmentation and pressure drop effects across various aspect ratios. The wedge is defined by height-to-hydraulic diameter ratio and wedge angle. The flow characteristics of wedge turbulators, such as horseshoe vortices are observed in a high Reynold’s number environment with supercritical hydrogen as the working fluid. Thermal performance efficiency is measured by Nusselt Number (Nu) and Pressure Loss.