Pulsed Jet Wake Generator for Consistent Turbomachinery Unsteadiness
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Solution Overview
Problem
Existing methods for simulating periodic unsteadiness in turbomachinery environments, such as moving rod wake generators, are intrusive due to their support structures, and stationary pneumatic devices lack consistency in generating velocity deficits and turbulence.
Innovation Solution
A periodic unsteadiness generator with a teardrop cross-section featuring leading and trailing edge jets, pulsed with compressed air to create uniform air distribution and adjustable parameters like jet supply pressure, frequency, and incidence angle, simulating wake-like disturbances without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If moving rod wake generators are used to simulate periodic flow disturbances, then continuous periodic disturbance propagation is achieved, but intrusive support structures (chains, sprockets, slots) are introduced
Solution Approach 1:
The patent replaces the mechanical moving rod system with a pneumatic system that uses compressed air pulses to generate wake-like disturbances. The pulsed pneumatic jets eliminate the need for physical moving components such as rods, chains, and sprockets, while still producing the desired periodic flow unsteadiness through pressure-driven fluid injection upstream of the blade row.
Solution Approach 2:
The invention employs compressed air pulses delivered through pneumatic jets to generate periodic wake disturbances. The pneumatic system uses pressure pulses to create velocity deficits and turbulence in the airflow, mimicking the effect of moving rods without requiring any mechanical moving parts. This approach uses gas dynamics to achieve the same flow modification goals.
2Device complexity
If stationary pneumatic devices are used to generate velocity deficits, then periodic disturbances are produced, but consistency in generating velocity deficits and turbulence is lacking
Solution Approach 1:
The patent implements periodic action by pulsing compressed air through the pneumatic jets at controlled frequencies. This periodic pulsing creates consistent, repeatable wake-like disturbances with uniform velocity deficits and turbulence characteristics. The periodic nature of the pressure pulses ensures that each disturbance cycle is identical, achieving the consistency that was lacking in previous stationary pneumatic devices.
Solution Approach 2:
The invention achieves consistency through precise control of pneumatic parameters including pulse frequency, supply pressure, and jet geometry. By carefully controlling these parameters, the device produces repeatable velocity deficits and turbulence intensity levels. The ability to adjust and maintain fixed parameter values ensures that each pulse generates the same flow disturbance characteristics.
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
Provides a consistent and cost-effective method to simulate periodic unsteadiness, allowing for a range of flow conditions without altering moving components, effectively mimicking upstream wake effects on turbomachinery flows.
Implementation Method 1
A periodic unsteadiness generator with a teardrop cross-section featuring leading and trailing edge jets, pulsed with compressed air to create uniform air distribution
Implementation Method 2
A first row of jets 104 are located along the leading edge, and a second row of jets 106 along the trailing edge of the device 100
Data Source
AI summary
The systems and methods provided herein are directed to a stationary device for simulating the periodic unsteadiness typically produced by turbines in an air stream. A streamlined body includes a line of jets along its leading edge that pulses air at an angle against the air stream, and a separate line of jets along its trailing edge to expel a sustained air flow in the same direction as the air stream.