Air Cycle Machine Compressor Housing for Seal Clearance Balance
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Solution Overview
Problem
Air Cycle Machines (ACMs) face challenges in minimizing friction losses and seal leakage, which lead to reduced turbine power transfer and potential bearing cooling flow blockages, due to the interaction between rotating shafts and static seals, resulting in sub-synchronous vibrations and excessive leakage.
Innovation Solution
The housing components of the ACM are designed with specific dimensions, including a main bore housing radius, static seal radius, shroud pilot housing radius, and insulator seal plate housing radius, to optimize seal clearance and minimize friction losses, prevent leakage, and maintain efficient airflow, thereby reducing sub-synchronous vibrations and ensuring adequate bearing cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If seal clearance is minimized to reduce leakage, then seal leakage is reduced, but friction losses increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the seal clearance dimension (0.002 to 0.006 inches) to optimize the balance between leakage reduction and friction minimization. This dimensional parameter optimization allows the seal to maintain adequate clearance while preventing excessive airflow leakage, thereby resolving the contradiction between reducing substance loss and energy loss.
2Loss of substance
If shaft excursions are constrained to minimize leakage, then seal leakage is reduced, but sub-synchronous vibrations increase
Solution Approach 1:
The patent utilizes parameter changes by optimizing the housing bore dimensions (main bore radius R1, shroud pilot radius R2, insulator seal plate radius R3) to create precise clearance gaps that accommodate shaft excursions while minimizing leakage. These dimensional parameters are carefully selected to allow controlled shaft movement without excessive leakage or harmful vibrations.
3Loss of energy
If seal clearance is optimized to reduce leakage, then turbine power transfer is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by defining specific housing dimension ranges (main bore radius R1, shroud pilot radius R2, insulator seal plate radius R3) that optimize turbine power transfer while accounting for manufacturing tolerances. These parameters are selected to achieve the desired performance within practical manufacturing capabilities, balancing efficiency improvement with manufacturability.
Data Source
AI summary
A component of an air cycle machine includes a fan housing portion, a compressor housing portion, a main bore housing radius, a static seal radius, a shroud pilot housing radius, and an insulator seal plate housing radius. The fan housing portion includes a shroud for a fan section. The compressor housing portion includes a shroud for a compressor air inlet, a shroud portion for a compressor blade section, and a shroud portion for a compressor air outlet. The main bore housing radius is arranged about a central axis and is configured to circumscribe a shaft arranged along the central axis, the main bore housing radius being between 1.9400 and 1.9440 inches. The static seal portion is arranged about the central axis and positioned longitudinally adjacent to the main bore housing portion. The static seal portion is configured to circumscribe a static seal defined by the shaft, and has a radius between 2.0420 and 2.0440 inches. The shroud pilot housing radius is arranged about the central axis. The shroud pilot housing radius is between 5.9440 and 5.9470 inches. The insulator seal plate housing radius is arranged about the central axis and is configured to mate with an adjacent turbine section component. The insulator seal plate housing radius is between 8.6380 and 8.6420 inches.