Calibrated air flow pulsator for flame turbulence control

(Journal publication)

A new device developed by CBOne for combustion stability testing is described in the Journal of Engineering for Gas Turbines and Power.

Air Flow Modulation for Refined Control of the Combustion Dynamics Using a Novel Actuator
Fabrice Giuliani, Andreas Lang, Klaus Johannes Gradl, Peter Siebenhofer, and Johannes Fritzer,
Journal of Engineering for Gas Turbines and Power 134, 021602 (2012),
DOI:10.1115/1.4004147

 

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This apparatus is used for two reasons. The first one is to determine whether a burner is steady or not, and what are the frequencies where there is a risk to meet a combustion instability. The second reason is flow control, where one wants to set the turbulence at a given rate so that no pulsation is met, but the turbulent energy is concentrated on a given energy peak which is not armful for the system.

It is known from previous works of authors that small perturbations on the air feed of flames can have a dramatic influence on their turbulence, provided the excitation frequency matches a resonant mode of the flame.

To this effect, a device able to withstand aggressive flow conditions (hot air, pressurised) was designed so that both frequencies and amplitude can be varied, this independently from each other.

The device helps to scan through the frequencies and find the resonant modi, as well as it can fine tune the level of excitation so that the desired effect is produced on the flame.

Here are some technical features of this apparatus:

- Frequency: from 0 to 1000 Hz

- Amplitude of modulation: from 0 to 35 %

- Air mass flow rate: 32 g/s @ 2 bar on the pressure side, ambient temperature

- Air flow temperature: tested up to 500K