Diffuser (thermodynamics)

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

Low pressure end diffuser for axial flow elastic fluid turbines

Abstract: An improved low pressure end diffuser for axial flow elastic fluid turbines, such as steam turbines, is disclosed. A housing is provided on the outer fairing member of the diffuser, which housing defines a vented chamber. The outer fairing member is provided with openings communicating between the chamber and the annular area within the turbine casing adjacent the leading edges of the last stage turbine blades. Injection slots are formed in the outer fairing member to communicate between the chamber and the exhaust outlet downstream of the trailing edges of the last stage turbine blades. The injection slots are formed in such a manner that the fluid will flow from the chamber along a major portion of the inner surface of the outer fairing member whereby fluid boundary layer on the fairing surface will be accelerated to prevent separation of the boundary layer from the surface thereby resulting in improved diffuser performance.

Laser liquid level gauge with diffuser

Abstract: The liquid level sensor includes a modulated laser diode and collimating optics for collimating the diode output to produce an optical measurement signal beam transmitted to the fluid boundary through a diffuser to diverge the beam. A detector detects reflections of the beam from the fluid boundary to produce an output signal which is amplified and inverted to drive the modulator. The frequency of the modulation, which depends on the distance to the fluid boundary, is measured and the distance is derived from that measurement.

Hand-held hair dryer

Abstract: A hand-held hair dryer has a housing that consists of a handle (12) and of an outer tube (14) through which air can flow. The outer tube (14) has an air flow inlet (16) and an air flow outlet (18) and means for generating and heating the air flow are provided in the housing. An inner tube (42) that receives at least the means for heating the air flow is arranged inside the outer tube (14). The inner tube (42) is made of a material with a higher thermal resistance than the outer tube and ends at least at the level of the outlet of the outer tube (14) or extends beyond the outlet of the outer tube (14) in the flow direction (64). A hair styling tool, for example a nozzle (44), a diffuser or the like, can be secured to the inner tube (42).

Experimental and Numerical Investigation of the Impact of Swirl on the Performance of Industrial Gas Turbines Exhaust Diffusers

Abstract: In order to investigate the effect of inlet conditions on the performance of an axial strutted annular exhaust diffuser, as used in heavy duty gas turbines, a scaled test-rig was built which allows the systematic variations of inlet conditions like inlet swirl, Mach number and turbulence level. This rig, which is of modular design, is used for the analysis of the flow-structures in typical GT-exhaust configurations and provides the performance data used in the diffuser design process. The present work shows the influence of inlet swirl and Mach number on the performance of a specific diffuser configuration. The first strut was designed for a certain flow angle distribution (so-called design conditions), and the measurements have been done for a range of inflow parameters including design and off-design conditions. The measurements allowed to reveal the impact of 3D effects on the diffuser characteristic. Comparison of measurements with correlations available from literature (annular diffuser configurations) show that the application of the latter is of limited use for the design of real GT diffusers, because standard correlations do not account for inlet swirl / struts interaction. The experimental data has been used to validate the numerical procedure developed by the authors for the analysis of axial GT exhaust diffusers. The results of computations are in reasonable agreement with measurements.Copyright © 2003 by ASME

Unsteady Transonic Flows in a Two-Dimensional Diffuser.

Abstract: : Extensive measurements of shock position and pressure distributions (wall static, core flow static, and core flow total) were made, complemented by spark schlieren and high-speed schlieren photographic information. Measurements were made at shock Mach numbers up to 1.35, with and without excitation. The excitation amplitudes were low, with frequencies from 0 to 330 Hz. Unexcited flows displayed two dominant natural frequencies for attached flows (shock Mach numbers below 1.27) and one dominant peak for separated flows (shock Mach numbers above 1.28). The dominant frequencies depend strongly on shock strength. Diffuser response to excitation appears to follow patterns expected on the basis of low-amplitude (acoustic) wave propagation concepts, provided that the stream-wise variation of the flow speed is considered and realistic boundary conditions are applied at the ends of the channel. The study strongly suggests that the effective acoustic impedance associated with the shock/boundary-layer interaction zone is an important determinant of diffuser response to small-amplitude external perturbations.