Diffuser (thermodynamics)

About: Diffuser (thermodynamics) is a research topic. Over the lifetime, 6731 publications have been published within this topic receiving 54738 citations.

Distinctions Between Two Types of Self Excited Gas Oscillations in Vaneless Radial Diffusers

Abstract: Experiments were conducted to determine the characteristics of oscillating flows in a centrifugal compression system with vaneless diffusers. The system was operated without a diffuser and with eight different diffuser configurations to determine the effects of diffuser diameter and width ratios on the unsteady behavior of the system. Mean and fluctuating velocity and static pressure measurements were carried out in the time and frequency domains. The system without a diffuser was found to be stable at all operating conditions. The installation of any of the eight diffusers resulted in the generation of self-excited oscillations at some operating conditions. It was found that the critical flow coefficient at which onset of oscillations was observed increased as the diffuser width ratio was decreased and as the diameter ratio was increased. Comparison between the characteristics of the oscillations observed in the present study and those observed by other investigators indicate that rotating stall in two geometrically similar diffusers can be an order of magnitude different in the non-dimensional rotational speed and level of unsteady pressure fluctuations. These differences point towards the possibility of existence of more than one set of flow conditions which could lead to the occurrence of the unsteady phenomena.Copyright © 1979 by ASME

Flow stabilizing device

Abstract: The present invention is a device (100) for at least partially stabilizing an unstable fluid flow within a flow channel (103) by capturing at least a portion of the unstable fluid within a vaneless diffuser having a diffuser slot ( 104 ). The present invention also includes maintaining and harnessing a substantial portion of the energy contained in the fluid as it flows through the diffuser in order to utilize the fluid to improve the condition of the flow field. An example of a beneficial use includes discharging the diffuser effluent into the flow at other points critical to instability, hence reducing the overall instability of the flow channel.

Gas turbine engine having slim-line nacelle

Abstract: A gas turbine engine system includes nacelle, a first boundary layer control device, a second boundary layer control device, at least one sensor, and a controller. The nacelle is defined about an axis and includes an inlet lip section, an inlet internal diffuser section, and a variable area fan nozzle moveable to influence a discharge airflow area of the nacelle. The first boundary layer control device is positioned near the inlet lip section and is actuable to introduce a first airflow at the inlet lip section. The second boundary layer control device is positioned near the inlet internal diffuser section and is actuable to introduce a second airflow at the inlet internal diffuser section. The sensor produces a signal that represents an operability condition. The controller receives the signal and simultaneously moves the variable area fan nozzle and actuates the first boundary layer control device and the second boundary layer control device in response to receiving the signal to achieve a slim-line nacelle.