M.S. Thesis Presentation by Anthony Meehan
Friday, June 18, 1999

(Dr. Ben Zinn, advisor)

"Steady State Response of an Axial Compression System to a Constant Heat Input"

Abstract

Axial compressor instabilities present a severe limitation upon compression system performance.  In the past, active control schemes desired to control these instabilities via downstream air bleeding actuation.  A new actuation method for controlling these instabilities is downstream fuel-burning.  In order to achieve this goal of fuel-burning actuation, the compression system response to a heat input must be examined experimentally, which is the main content of the work presented here.

In order to accomplish this goal of examining compression system behavior, a fuel burning actuation system capable of static and dynamic, as well as open and closed loop, commands was installed in an existing axial compression system.  In addition, this actuation system was calibrated and dynamically characterized.

Once this actuation system was implemented, the steady state response of the compression system was observed.  The behavior of the dependent system variables (pressure, temperature, mass flow rate and rotating stall amplitude) was obtained for varying values of the independent system variables of heat input and main throttle position.  A number of interesting results were obtained from these tests, the most important of these being the analogous behavior between heat input and throttle position.  This analogous behavior between heat input and throttling implies that downstream heat addition may be used to control compressor operation.

Lastly, a steady state heat loss model for the compression system was developed.  This model was able to accurately predict the compression system’s exit temperature.  This heat loss model also allowed for calculations that yielded information concerning the compression system’s static temperature sensitivity as well as its steady state thermal efficiency.  Essentially, the heat loss model allowed for quantification of the steady state “effectiveness” of the heat input.