A Study of Performance Improvement for High Specific Speed Centrifugal Compressors by Using Diffusers With Half Guide Vanes

1987 ◽  
Vol 109 (4) ◽  
pp. 359-366 ◽  
Author(s):  
Y. Yoshinaga ◽  
T. Kaneki ◽  
H. Kobayashi ◽  
M. Hoshino
Keyword(s):  
Performance Improvement ◽  
Side Wall ◽  
Axial Direction ◽  
Pressure Recovery ◽  
Guide Vanes ◽  
Small Height ◽  
Optimum Height ◽  
New Type ◽  
Specific Speed ◽  
Width Measurements

The experimental results from eighteen different centrifugal compressor stages showed that the pressure recovery of vaneless diffusers for high specific speed compressors was extremely low compared with the value expected by an ideal two-dimensional analysis. Consequently a new type of diffuser with half guide vanes on the shroud side wall was proposed. The pressure recovery of this diffuser at distorted inlet flow was considerably improved by the half guide vanes. The optimum height of the vanes was a little less than one half of the diffuser width. Measurements of the velocity distribution in the diffusers using Pitot tubes and a laser-two-focus velocimeter, clearly showed that the small height guide vanes gave a uniform flow in the axial direction and improved the pressure recovery of the diffuser.

Hot Spline Forming of Ultra-High Strength Steel Gear Drum Using Resistance Heating

2014 ◽  
Vol 622-623 ◽  
pp. 201-206 ◽  
Author(s):  
Kenichiro Mori ◽  
Tomoyoshi Maeno ◽  
Shohei Nakamoto
Keyword(s):  
Deep Drawing ◽  
High Strength Steel ◽  
Side Wall ◽  
High Strength ◽  
Axial Direction ◽  
Resistance Heating ◽  
Sectional Area ◽  
Forming Process ◽  
Cross Sectional ◽  
Ultra High Strength Steel

A hot spline forming process of die-quenched gear drums using resistance heating of a side wall of a cup formed by cold deep drawing and ironing was developed. The side wall having uniform cross-sectional area is resistance-heated by passage of the current in the axial direction, the heated side wall of the drawn cup is ironed and is finally die-quenched. The gear drum was successfully formed and the hardness was between 400 and 500 HV. Not only the formability was improved but also the formed dram was hardly oxidised because of rapid resistance heating.

Construction Technology of Shallow Pipe- Jacking Working Shaft

2011 ◽  
Vol 480-481 ◽  
pp. 1266-1270
Author(s):  
Liu Hui
Keyword(s):  
Side Wall ◽  
Soil Mass ◽  
Construction Method ◽  
Construction Technology ◽  
Reactive Force ◽  
Small Height ◽  
Key Points ◽  
Pipe Jacking ◽  
Design And Construction

During the pipe jacking construction, the bearing plates of jack need the support of great reactive force which is provided by the side-wall of the working shaft and the soil mass behind the wall. In the shallow pipe-jacking working shaft, the soil mass only can provide limited reactive force due to the small height of the soil mass behind the side-wall, which becomes the difficult point in the design and construction of the shallow pipe-jacking working shaft. This thesis takes the actual projects for the examples to introduce the construction technology of shallow pipe-jacking working shaft in details, including the construction key points like pre-grouting injection consolidation, ring beam construction method as well as reverse construction method.

Unsteady Flow at the Outlet of the High Specific Speed Centrifugal Compressor Impeller

1984 ◽  
Author(s):  
Fumikata Kano ◽  
Takafumi Shirakami
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Compressor ◽  
Coal Gasification ◽  
Three Dimensional ◽  
Axial Direction ◽  
Navier Stokes ◽  
Meridional Plane ◽  
Mixed Flow ◽  
Navier Stokes Equation ◽  
Specific Speed

The unsteady flow at the outlet of the high specific speed mixed flow Impeller was studied. The specific speed is 500 (m3/min)1/2 · rpm · m−3/4. The flow is strongly influenced by the impeller blading. The other hand, the flow influences the performance of the stationary vanes downstream of the impeller. The flow path at the outlet of the mixed flow impeller is inclined to the axial direction and is curved in the meridional plane. The study was carried out to develop the 30 MW centrifugal compressor. This compressor is used in the field of the coal gasification, the geothermal power generation, etc. The distributions of flow velocity, pressure and temperature of three dimensional flow were measured using a high sensitive pressure transducer and a total temperature probe. The flow was surveyed across the entire passage at about ten axial locations including endwall boundary layer. A theoretical analysis was also carried out using the linearized Navier-Stokes equation.

scholarly journals Flow through Guide Vanes of Low Specific Speed Mixed Flow Pumps.

1993 ◽  
Vol 59 (568) ◽  
pp. 3831-3837
Author(s):  
Toshiaki Kanemoto ◽  
Hirotaka Akamatsu ◽  
Shigenori Matsunaga ◽  
Hiroshi Tsukamoto
Keyword(s):  
Mixed Flow ◽  
Guide Vanes ◽  
Flow Through ◽  
Low Specific Speed ◽  
Specific Speed

scholarly journals Optical trapping by petal-like circular Airy beam

2020 ◽  
Author(s):  
Vahid Shahabadi ◽  
Daryoush Abdollahpour
Keyword(s):  
Optical Trapping ◽  
Radial Distance ◽  
Transverse Field ◽  
Axial Direction ◽  
Axial Position ◽  
Trapped Particles ◽  
Airy Beam ◽  
Tight Focusing ◽  
New Type ◽  
Beam Parameters

Abstract Superposition of two circular Airy vortex beams (CAVB), with opposite sign topological charges (l), produces a new type of petal beams called petal-like circular Airy beam (PCAB) with a transverse field distribution in the form of azimuthally modulated concentric rings that follow Airy function over the radial distance on a transverse plane. In this paper, tight focusing of truncated PCAB and its application in optical trapping is numerically investigated. It is shown that by adjusting the beam parameters four different trapping configurations can be achieved: a single transverse trap at a single axial position, a multi-trap geometry at a single axial position, two single transverse traps at two positions along the axial direction, and two multi-trap geometries at two different axial positions. It is also shown that the number of trapped particles in the multi-trap configurations is 2l per focal plane, while the number of axial trap positions is determined by the truncation aperture size. Finally, trap stiffnesses and corresponding potential energies for the trapping configurations are presented and discussed.

Sign in / Sign up

Export Citation Format

Share Document