Turbine Diffuser Nozzle With Varying Radial Spacing
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Solution Overview
Problem
Conventional diffuser-nozzle assemblies in turbomachines with axial or radial configurations face challenges in achieving uniform air flow and high fuel atomization, leading to combustion instability due to circumferential non-uniformities in air speed at the nozzle outlet, resulting in large head losses and potential combustion instability.
Innovation Solution
A diffuser-nozzle assembly with cylindrical walls connected by radial vanes, where the radial spacing between the walls varies circumferentially to be minimum at the vane locations and maximum between them, and optionally featuring corrugated or crenellated downstream walls to further reduce non-uniformities and accelerate air flow in the vane wakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional axial or radial diffuser-nozzle assemblies are used, then the structure is simple and easy to manufacture, but the air flow uniformity at the nozzle outlet deteriorates due to circumferential non-uniformities in Mach number
Solution Approach 1:
The patent applies local quality by varying the radial spacing between the inner and outer cylindrical walls of the nozzle in different circumferential locations. Specifically, the spacing is minimized at locations corresponding to the wakes of the vanes and maximized between the vanes, creating locally optimized flow conditions throughout the nozzle structure. This local variation in geometry corrects the circumferential non-uniformities in Mach number without requiring a complete redesign of the entire nozzle system.
2Speed
If the radial spacing between nozzle walls is reduced to accelerate air in vane wakes, then the air speed uniformity improves, but the head loss increases due to the smaller flow passage
Solution Approach 1:
The patent applies local quality by varying the radial spacing between the inner and outer cylindrical walls of the nozzle in different circumferential locations. Specifically, the spacing is minimized at locations corresponding to the wakes of the vanes and maximized between the vanes, creating locally optimized flow conditions throughout the nozzle structure. This local variation in geometry corrects the circumferential non-uniformities in Mach number without requiring a complete redesign of the entire nozzle system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances air flow uniformity, reduces head losses, and stabilizes combustion by minimizing speed differences across the nozzle outlet, allowing for a more efficient fuel atomization and potentially reducing the weight of the turbomachine by shortening the nozzle-injector distance.
Implementation Method 1
Minimizing the radial spacing between the inner and outer walls of the nozzle in register with the vanes and downstream therefrom serves to accelerate the air stream locally in the wakes of the vanes as compared to the air stream that passes between the vanes
Data Source
AI summary
A diffuser-nozzle assembly for mounting at an outlet from a compressor in a turbomachine, the assembly including a nozzle including two substantially cylindrical walls, a radially inner wall and a radially outer wall that are connected together by radial vanes. The walls of the nozzle are extended downstream beyond the radial vanes and the radial spacing therebetween varies downstream from the vanes to be at a minimum substantially in register with the vanes and at a maximum between the vanes.