Valves - Fuel Flow Modulator Valves

Fuel flow Modulator Valves for Combustion Control

Midé's fuel flow modulation valves (actuators) represent a key technology area required for demonstration of an active combustion control system in augmentor applications.

Active combustion control (ACC) in augmentor platforms may attenuate combustion instabilities such as 'rumble' and 'screech', leading to a wider performance envelope and maintenance cost savings due to reduced component fatigue.

The envisioned ACC system consists of precise feedback-based manipulation of the fuel injection. This provides an adaptive means to manage mixing, heat release, exit temperature, and exit emissions from the combustor, resulting in reduction or elimination of combustion instabilities. Sensors feed combustion pressure fluctuation measurements to the controller, which governs the valves or actuators that modulate the incoming fuel flow. This modulation is adaptively synchronized to produce heat release profiles 180° out-of-phase with the instability such that unwanted thermoacoustic fluctuations are effectively cancelled out, stabilizing the combustion.

Midé's Generation 3 Fuel Flow Valve/Actuator for combustion control

Through an Air Force SBIR program, Midé has developed fuel flow actuators to a TRL 4, designed for integration into a screech reduction ACC system. One set of Generation 2 valves has already been used to demonstrate instability attenuation on a three flameholder combustion rig. Characteristics of the Generation 3 two-position (digital), two-way prototype valves include the following:

• High speed - at least 600 Hz modulation rate.
• High temperature - 350 °C operation capability.
• High pressure - up to 2000 psia working pressure.
• High flowrate - over 10,000 pph JP-8 maximum.
• Lightweight - less than 1 lb.
• Small - envelope is 2x3x2".
• Flexibile - accommodates mean flowrate adjustment.

Midé's Generation 3 Fuel Flow Actuator Prototype Characteristics

	Typical	Min-Max	Units
Electrical
Supply Voltage	48	24-48	VDC
Peak Supply Current	34	-	A
Energy per Cycle	490	-	mJ
Hydraulic
Flow Number[1] (Open)	250	-	pph/?psi
Supply Pressure	-	0-2000	psig
Flowrate	-	0-10,000	pph
External Leakage	0	-	pph
Fluid Temperature	20	10-100	°C
Inlet Interface	SAE 6 port	-
Outlet Interface	Custom	-
Mechanical
Approx. Dimensions	2 x 3 x 2	-	in
Approx. Weight	1	-	lbs
Step Response	500	-	ms
Bandwidth	-	1-600	Hz
Duty Cycle[2]	50%	-
Environmental
Operating Temperature[3]	20	10-350	°C

[1] for working fluid having specific gravity 0.82 and kinematic viscosity 3.8 cSt at 20 °C
[2] pulse width limited
[3] estimate based on Generation 2 hardware and tests that demonstrated 350 °C operation.

Simplified example of an active combustion control
system for augmentor screech reduction

For more information:

Please email Attila Lengyel (Products), or call: 781-306-0609 x225