Flow Through Cascades of Slotted Compressor Blades

1970 ◽  
Vol 92 (1) ◽  
pp. 57-64 ◽  
Author(s):  
A. A. Mikolajczak ◽  
H. D. Weingold ◽  
J. P. Nikkanen
Keyword(s):  
Flow Analysis ◽  
Axial Flow ◽  
Limited Range ◽  
Wall Region ◽  
Compressor Blades ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Flow Through ◽  
Wake Model ◽  
End Wall

The performance of axial flow compressors can be improved when it becomes possible to achieve higher loading per stage than currently attainable. The major obstacles to attaining this objective are the limitations on loading in the end wall region and the limited range of operating incidence of compressor blades. A possible method of achieving a wide range of operating incidence is the use of slotted or multibody airfoils. An incompressible, two-dimensional, potential flow analysis for thick, highly cambered multibodies in cascade is presented. The analysis is extended to include compressibility. A boundary-layer calculation, including a wake model, is described and used to predict cascade losses. Theoretical predictions are compared against slotted and unslotted cascade and compressor stator experimental results and adequate agreement obtained. The slotted blade concept is shown to offer performance benefits, provided that end-wall loading limitations can be overcome.

Performance Study of a Mixed Flow Impeller Covering an Unsteady Flow Field

1992 ◽  
Vol 206 (2) ◽  
pp. 83-93 ◽  
Author(s):  
S Sarkar
Keyword(s):  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Performance Study ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Wide Range ◽  
Reversal Flow ◽  
Flow Through ◽  
Flow Pump

The results presented here are part of a detailed programme measuring the aerodynamics of a high specific speed mixed flow pump impeller over a wide range of operating conditions, including its behaviour in the unsteady stalled regime. The aim is to elucidate the physics of the flow through such an impeller. The noticeable features are the formation of part-span rotating stall cells having no periodicity and organized structure at reduced flow and also the shifting positions of reversal flow pockets as the flowrate changes. Measurements of loss and its variation with span-wise positions and flowrates enable the variation of local efficiency to be determined. The overall flow picture is similar to that expected in an axial flow impeller, though the present impeller displays a narrow stall hysteresis loop almost right through its operating range.

Steady Compressible Flow through a Single Row of Radial Holes in the Wall of a Pipeline

1970 ◽  
Vol 12 (4) ◽  
pp. 248-258 ◽  
Author(s):  
G. H. Trengrouse
Keyword(s):  
Discharge Coefficient ◽  
Pressure Change ◽  
Single Row ◽  
One Dimensional ◽  
Discharge Coefficients ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Flow Through ◽  
Flow Theories ◽  
Good Agreement

Measured values of discharge coefficient for air flow through a single row of radial holes in the wall of a pipeline are reported, together with the values of pipe Mach numbers in the immediate vicinity of the holes. A wide range of pressure and area ratios are considered, the flow through the holes being either into or out of the pipe. It is shown that the effects on the measured values of both the pressure level at discharge from the holes and the air temperature are negligible. The agreement between the pressure change in the pipeline due to the holes, obtained experimentally, and that predicted by simple, one-dimensional flow theories is generally unsatisfactory. However, theoretical predictions of the jet efflux angles based on two-dimensional, incompressible, non-viscous flow arguments are in good agreement with those measured, but discrepancies do arise in the prediction of discharge coefficients.

scholarly journals Modeling of Cavitating Flow through Waterjet Propulsors

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Jules W. Lindau ◽  
Christopher Pena ◽  
Warren J. Baker ◽  
James J. Dreyer ◽  
William L. Moody ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Total Pressure ◽  
Axial Flow ◽  
Flow Coefficient ◽  
Experimental Measurements ◽  
Computational Results ◽  
Suction Surface ◽  
Blade Passage ◽  
Wide Range ◽  
Flow Through

A computational-fluid-dynamics-based modeling effort to capture flow through an axial flow waterjet propulsor is presented. The effort covered the waterjet flow over a wide range of flow coefficients and into cavitation-driven breakdown. The computations are presented in cavitation at two values of flow coefficient through a series of decreasing operating inlet total pressure. The computational results are compared to experimental measurements. Suction-surface and tip-gap cavitation patterns are presented and compared to experimental photographs. Presented computational solutions are blade-passage steady and periodic. The computational results apply a powering iteration methodology to facilitate coupling of rotor, stator, and inflow and outflow ducting.

scholarly journals Propagating Stall in Compressors With Porous Walls

1975 ◽  
Author(s):  
J. H. Horlock ◽  
C. M. Lakhwani
Keyword(s):  
Unsteady Flow ◽  
Radial Flow ◽  
Flow Instability ◽  
Porous Wall ◽  
Flow Coefficient ◽  
Compressor Blades ◽  
Axial Compressors ◽  
Flow Through ◽  
Porous Walls ◽  
End Wall

A modification is presented to the Emmons/Stenning analysis for predicting stall propagation, taking into account the unsteady flow through the end wall of a cascade row of compressor blades. It is shown that if radial flow from the blade channels is permitted, then the condition for flow instability is changed. The expression obtained for the flow coefficient at which stall occurs indicates an improvement in operating range, with virtually no effect on stall cell speed. Experimental evidence suggests that a mechanism such as that described may be the reason for the delay in stall onset produced by porous wall treatment of axial compressors.

A Fast Numerical Procedure to Solve the Meridional Equations of Motion in a Multistage Axial Flow Turbomachine

1981 ◽  
Author(s):  
A. Kündig
Keyword(s):  
Equations Of Motion ◽  
Computing Time ◽  
Axial Flow ◽  
Numerical Procedure ◽  
Flow Conditions ◽  
Compressor Blades ◽  
Streamline Curvature ◽  
Downstream Flow ◽  
Real Flow ◽  
End Wall

A new numerical procedure has been developed to solve the meridional equations of motion in an axial flow turbomachine. It is based on the so-called streamline-curvature method. The primary aim of this project was to reduce the computing-time of existing programs. The procedure has been tested. The new program is coupled with a program for the calculation of end-wall-boundary layers on axial flow compressors. This combination makes the simulation of real flow conditions possible. The pitch wise deviation angles and blade-row efficiencies are generally given as input. For compressor blades of the NACA-65-family they can be called from stored empirical data as function of geometry and the upstream and downstream flow conditions. The paper presents an exact description of the numerical procedure and a computed example.

Secondary Flow in Repeating Stages of Axial Turbomachines

1995 ◽  
Vol 209 (2) ◽  
pp. 101-110 ◽  
Author(s):  
J H Horlock
Keyword(s):  
Experimental Data ◽  
Secondary Flow ◽  
Flow Analysis ◽  
Axial Flow ◽  
Streamwise Vorticity ◽  
Flow Phenomenon ◽  
Multi Stage ◽  
Axial Velocity Profile ◽  
Flow Through ◽  
Flow Compressor

In a well-designed multi-stage axial flow compressor, the flow settles down to a repeating condition, in which the axial velocity profile does not deteriorate further; it is more or less unchanged between the entry and the exit of a deeply embedded stage. However, experimental data also show that the flow angles repeat, and it is this flow phenomenon that is discussed in the paper. Secondary flow analysis, coupled with empirical data on clearance flows, is used to give a description of the flow in such a repeating stage. The secondary flow at exit from a row involves both the streamwise vorticity generated in that row and the vorticity that exists at entry—the so-called ‘skew’ vorticity due to a non-uniform velocity from a stator being received by a moving rotor (and a similar effect from the rotor to the stator). However, clearance vorticity—shed from the rotor tip (casing) section and the stator root (hub) section—is also present and can be taken into account. Calculations made using the analyses are compared with some limited experimental data drawn from the published literature. Predicted underturning at rotor tip (casing) sections is confirmed by experiments; similarly, predicted underturning at stator tip (casing) sections accords with observations in one compressor but not in another. However, no universal conclusion (on whether underturning or overturning usually occurs) can be drawn for the flow through the rotor and stator root (hub) sections, as either entry or generated secondary vorticity may dominate.

Retarded Flow of Bingham Materials

1959 ◽  
Vol 26 (1) ◽  
pp. 107-113
Author(s):  
Alfred Slibar ◽  
Paul R. Paslay
Keyword(s):  
Couette Flow ◽  
Axial Flow ◽  
Experimental Results ◽  
Circular Pipe ◽  
Parallel Plates ◽  
Viscous Material ◽  
Concentric Cylinders ◽  
Bingham Material ◽  
Theoretical Predictions ◽  
Flow Through

Abstract The solutions for three cases of retarded flow of a rigid-viscous material are given. These cases are: (a) Sliding parallel plates; (b) Couette flow between concentric cylinders; and (c) axial flow through a circular pipe. For Couette flow two types of loading-unloading paths are found. The results of this analysis explain some of the discrepancies between experimental results and theoretical predictions for a Bingham material.

Boundary Layer Optimization for the Design of High Turning Axial Flow Compressor Blades

1971 ◽  
Vol 93 (1) ◽  
pp. 147-154 ◽  
Author(s):  
K. D. Papailiou
Keyword(s):  
Boundary Layer ◽  
Axial Flow ◽  
Optimization Method ◽  
Mapping Method ◽  
Compressor Cascade ◽  
Compressor Blades ◽  
Conformal Mapping Method ◽  
Theoretical Predictions ◽  
Flow Convergence ◽  
Flow Compressor

An optimization method, based on Le Foll’s boundary layer theory and on Goldstein’s conformal mapping method is described. The parameters of optimization are circulation per blade and absolute losses. The problem is treated as an inverse problem (i.e., the best blading is found starting from the flow conditions imposed). The performance of a highly loaded compressor cascade, designed according to the method presented and tested in a low speed wind tunnel, is compared with the theoretical predictions. Some discrepancies exist which are due to the influence of flow convergence and blade curvature. A modification of the method to take into account these effects is discussed.

Gluten-Free Dry Mixtures with Rice and Amaranth for Children over Three Years Old with Gluten Intolerance

Food Industry ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 23-31
Author(s):  
Sergey Urubkov ◽  
Svetlana Khovanskaya ◽  
Ekaterina Pyrieva ◽  
Olga Georgieva ◽  
Stanislav Smirnov
Keyword(s):  
Celiac Disease ◽  
Treatment Effectiveness ◽  
Raw Materials ◽  
Calculated Data ◽  
Limited Range ◽  
Gluten Free ◽  
Fruit And Vegetable ◽  
Organoleptic Evaluation ◽  
Free Products ◽  
Wide Range

Diet therapy is one of the main approaches to the treatment of a wide range of diseases of the digestive system. The treatment effectiveness of celiac disease depends on how strictly the patient adheres to a gluten-free diet. It is often disrupted due to the limited range of recommended foods and dishes, especially for children who are particularly sensitive to dietary restrictions. In this case, the development of new types of specialized gluten-free products is relevant, allowing to expand the diet both in terms of nutritional value and taste diversity. This study concerns the recipe developments of dry gluten-free mixtures using rice and amaranth with the inclusion of fruit and vegetable and berry raw materials intended for the nutrition of children over three years old suffering from celiac disease. When developing the recipes, researchers used various combinations of rice and amaranth flour, as well as fruit and vegetable powders. The rice flour composition varied in the range from 15 to 75%; amaranth – from 15 to 45%; fruit and vegetable and berry powders – up to 10%. The finished product was gluten-free cookies, muffins, pancakes made of rice and amaranth. Organoleptic evaluation showed that the studied samples of gluten-free cookies have high quality characteristics, have a pleasant taste and aroma. According to the calculated data, specialized gluten-free dry mixtures intended for children over three years with celiac disease can serve as an important source of: vegetable carbohydrates – from 26.81 to 55.19 g / 100g of finished products; protein – from 4.06 to 11.82 g/100g of finished products; dietary fiber – from 3.82 to 6.36 g/100g of finished products; and energy – from 158.12 to 333.96 kcal/100g of finished products) The developed recipess of gluten-free products can help to provide children with an adequate amount of nutrients and energy.

Flow through axial-flow-turbomachinery blading

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Flow Velocity ◽  
Compressible Flow ◽  
Dimensional Analysis ◽  
Incompressible Flow ◽  
Compressible Fluid ◽  
Axial Flow ◽  
Linear Cascade ◽  
Dimensional Parameters ◽  
Flow Through

This chapter is concerned primarily with the flow of a compressible fluid through stationary and moving blading, for the most part using the analysis introduced in Chapter 11. The principles of dimensional analysis are applied to determine the appropriate non-dimensional parameters to characterise the performance of a turbomachine. The analysis of incompressible flow through a linear cascade of aerofoil-like blades is followed by the analysis of compressible flow. Velocity triangles for flow relative to blades, and Euler’s turbomachinery equation, are introduced to analyse flow through a rotor. The concepts introduced are applied to the analysis of an axial-turbomachine stage comprising a stator and a rotor, which applies to either a compressor or a turbine.

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