Topic
Diffuser (thermodynamics)
About: Diffuser (thermodynamics) is a research topic. Over the lifetime, 6731 publications have been published within this topic receiving 54738 citations.
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TL;DR: In this paper, the instantaneous vortical flow structure is one of the typical flow structures inside the nuclear reactor coolant pump (RCP), which would cause the unsteady pressure pulsations, vibrations of the unit and fatigue of components.
34 citations
Patent•
03 Oct 2006
TL;DR: In this article, a diffuser is designed with a series of fluid (gas and/or liquid) passages of equal effective length/flow resistance, such that as the fluid passes through the diffuser, the gas exits all areas at the same time and with the same mass flux.
Abstract: Uniform fluid delivery to a substrate is provider using a diffuser. The diffuser is designed with a series of fluid (gas and/or liquid) passages of equal effective length/flow resistance, such that as the fluid passes through the diffuser, the gas exits all areas at the same time and with the same mass flux. These passages may not be physically the same, however they have the same effective length and flow resistance. The diffuser can be implemented using single or multiple stacked layers, and from several to many passages. The net effect is a uniform gas curtain to the wafer. Since the passages through the diffuser are effectively the same, the uniform gas curtain to the wafer is not sensitive to the quantity of gas, the gas flow rate or the gas pressure. Additionally, a faceplate can optionally be used to smooth out any jet effects of the diffuser exit holes.
34 citations
TL;DR: The improvement of diodicity promises a simple pumping concept at low Reynolds numbers for lab-on-a-chip applications and anisotropic behavior can be achieved with viscoelastic effects.
Abstract: This paper reports the improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids. Since rectification in a diffuser/nozzle structure with Newtonian fluids is caused by inertial effects, micropumps based on this concept require a relatively high Reynolds numbers and high pumping frequencies. In applications with relatively low Reynolds numbers, anisotropic behavior can be achieved with viscoelastic effects. In our investigations, a solution of dilute polyethylene oxide was used as the viscoelastic fluid. A microfluidic device was fabricated in silicon using deep reactive ion etching. The microfluidic device consists of access ports for pressure measurement, and a series of ten diffuser/nozzle structures. Measurements were carried out for diffuser/nozzle structures with opening angles ranging from 15° to 60°. Flow visualization, pressure drop and diodicity of de-ionized water and the viscoelastic fluid were compared and discussed. The improvement of diodicity promises a sim...
34 citations
TL;DR: In this article, the potential interaction between the impeller and the diffuser blades appears more strongly than the impellers-wake interaction, and the presence of the peripheral blade surface with an outlet edge of the pressure surface causes violent pressure fluctuations in the vaned diffuser.
Abstract: Periodic flows downstream from a centrifugal pump impeller in vaneless and vaned diffusers were measured by using a single hole yawmeter and a phase-locked sampling method. The flows were also calculated by an inviscid flow analysis using the blade-surface singularity method. The periodic variations in calculated static pressure with the impeller rotating quantitatively agree well with the measured ones. The flow behaviors in the vaned diffuser are discussed, citing measured and calculated results. The potential interaction between the impeller and the diffuser blades appears more strongly than the impeller-wake interaction. The appearance of static pressure fluctuations due to the impeller's rotating in the fully vaned zone is different from that in the semivaned zone of the diffuser. The existence of the peripheral blade surface of the impeller outlet with an outlet edge of the pressure surface causes violent pressure fluctuations in the vaned diffuser.
34 citations
Patent•
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09 Apr 1984
TL;DR: In this article, a hair dryer improvement for varying the air flow output from the hair dryers nozzle is described, which is a diffusion device which consists of a pair of vanes pivotally mounted downstream of the nozzle.
Abstract: A diffusion device is provided within or as an attachment to the nozzle of a hair dryer which provides a nearly constant air volume at varying velocities. A hair dryer improvement for varying the air flow output from the hair dryer nozzle. The improvement is a diffusion device which consists of a pair of vanes pivotally mounted downstream of the nozzle. Placement of the vanes in varying positions causes the output air flow to be either concentrated along the nozzle axis or diffused by causing varying portions of the air flow to be directed through the peripheral side wall of the diffusion device. Since the diffusion device offers very little obstruction to the air flow, the volume of air remains nearly constant for the varying diffuser vane positions.
34 citations