High Pressure Compressor Using an Axial-Flow, Mixed-Flow, and Centrifugal Stage with Interstage and Disc

High Pressure Compressor (HPC) pressure ratios of up to 40:1 are required to achieve 100:1 cycle pressure ratios. A multi-stage axial HPC configuration will be too long and heavy and too inefficient in later stages (at these higher pressure ratios). Increased tip clearance to span ratio will also lead to low efficiency and surge margin for the axial HPC. The innovations of the proposed work include: (1) an axial-flow, mixed-flow, and centrifugal compressor (AMC) with each operating at or near its respective optimum specific speed (with a common rotational speed for all three stages); and (2) the diffuser system of the mixed-flow and centrifugal stages lending itself to using the bypass flow for interstage and discharge cooling. The interstage cooling improves cycle efficiency and specific thrust (thrust/mass flow) and allows for a smaller third stage impeller. The discharge cooling provides increased thrust/weight ratio for a given turbine inlet temperature. Phase I includes detailed cycle evaluations, heat transfer calculations, and preliminary stage designs (including novel weight/strength treatments). A developed HPC design will be provided in Phase II. Simplicity, ruggedness, improved performance, and optimized frontal area are implicit with the AMC configuration versus other existing or potential HPC options.