DE1628227A1 - Diffuser without guide vanes - Google Patents

Description

Diffuser without a guide on

The present invention relates to the diffuser section of a Tdicn1; er or a turbine and in particular to an improved contour of the diffuser walls for the purpose of increasing the efficiency of a compressor or the like

The subject of the state of the art is. Diffusers without jets either with parallel vents, diverging walls or with regional training for gltioiibjelbeijdtii KIuB made without baffles on the; ipeai, · !! * _; ^: J «hf ^ e <^ in | i _; d # rf ^ teeschiolii ^ biopiing and 'the accompanying wall friction losses. "■ ■; '; ■ ^: - ~:?>~;.,.

/ "- At- let eiä 2t * l d ·» present invention, a Diffuser without guide vanes, remove its contours especially * on the achievement of a «Höchat efficiency degree possible low »loss due to friction and heat has been calculated." -

Patent Attorneys DipJ.-lng. Martin borrowed », Dipl.-Wirtidi.-lno. Axel Hanimann, Phyi graduate. Sebastian Herrmann I MÖNCHEN %, THEtESIiNlTHAiSI 33 · T «Mmi392102 · T« l «gramm-Adr« u ·. Upatll / MOndiM

BankvaiUirfüngMi Dwhdw lenk AO, RIIaI * AMndiM, Dop.-Keii »Vikhiallanmortt, Κοηί» · Μτ. ΤήβΟΙ Bay "r.Vtr" intfconkMOnd> .n, Zw "! Gst. Oikar-ten-Mlllw-mna.tCto.-No. 1134 «· PofhdiKk-Konfo. MOneMn No. 143J »7

BATH

The invention is here in connection with a * ^; Hadiai flow compressor disclosed, but is just as useful'-in axial and semi-axial compressors or turbines *

The way by which the invention is carried out in practice, can best be understood from the following description, drawings in reference to the accompanying ge -, _{_.} Is accepted.

Figure 1 is an axial section through a typical one Centrifugal compressor; its diffuser is designed as a pattern of the present invention.

Figure 2 is a partial section showing a modified one Diffuser profile.

Figures 5 to 6 inclusive are schematic

Views and illustrate typical of a fluid Flow distribution images through a delimited space, such as e.g. through a diffuser »

FIG. 7 is an enlarged view of the diffuser profile of FIG.

Figure 8 is a diagram of the örenzacfeiefttparaaeter * G as jPtoüctien des erenxaohichtparaaeters I ^. - "- '- · -. -

The compressor shown in FIG. 1 contains a housing 10 and a shaft 12 which, in order to rotate an impeller 14 sitting on it, is driven by non-inclined means; the impeller has rotor blades 15. The fluid to be compressed enters the housing parallel to the shaft axis viewed from the left in FIG. 1 and is compressed by the impeller and radially outwards through an annular

0 09836/0561

Shaped diffuser without Leitschatifein joint *, the one in figure 1 "is shown at 16 * In Figure 1, both correspond Diffusqrwand the basic idea of the present invention. In Figure 2, a modification 16 'is shown in the a similar diffuser with a flat wall is shown ' is; his other wall has contours to give a similar result to reach.

The present invention is based on the calculation of a diffuser profile through .application to.-known Formulas with the aim of a state of the best flow through most of the diffuser length. The efficiency The iluidum flow through a delimited tree is considerably influenced by the arenium layer requirements for the effect of the fluid in the vicinity of the room walls. Some Boundary layer states are in Figures 3 to 6. "including illustrates the speed profile of a show fluid flowing within the passage walls. “As shown in Figures 3, 4 and 5, is the river in the main or middle part of the fluid flow uniform, while the boundary layer or the The river near the walls of the passage varies considerably under different conditions of speed. " changes in pressure, temperature, density and other factors.

Under certain conditions there is a tin-detached boundary layer with a velocity gradient in the vicinity of the walls of less than 90%, which is illustrated in FIG. 4 and means high friction and conversion

kinetic energy in vfärme _o FIG. 5 shows a condition that dis ¹ is one; The detached boundary layer means in which; - however, the gradient is greater than 90 ° and a reversal curve in the speed profile is created. This reversal curve: can be seen through the enlargement in FIG. , the. an even bigger one. AhfäüIL in the degree of efficiency and in the extent of the river means: as ^ die> in figure Λ veasan, - schaulich.fee. Condition"

The best conditions are! in the figure: 5- shown _r . the. This is close: imminent Gr enzacliich tab solution with an aEi gradient in 7 / andnä-Ete of about- 9Q ^ vtiranBeihauli.cJat- «

The present invention, ateicict gpurEälätzlleii in dear creation; of a DIffuser, the other; For the greater part of its size, the effective speed figure 11 of the type illustrated in FIG. This is achieved by a contour of the diffuser wall which, according to the areas 18, IS and 2G shown in FIG. 1, initially converges, then diverges and finally converges again.

The area represented by the route 1; S in FIG has a converging cross-section, which is intended to bring about acceleration up to a constriction point 21 :. ; this acceleration sets the. »<Despair, caused by the blades 15 of the compressor is. Region 19 has a diverging cross-section and therefore causes a flow apart up to the point ■ 22, where an imminent boundary layer separation occurs will. Beyond this point and up to the exit point,

00988670561

thus in the region of 20, the contours of the Florwands are developed in such a way that they can rightly maintain the situation of imminent separation of the boundary layer _; as shown by the three typical speed tests 25, 2β and 27 for this area *

The following is an application of known forraelai for illustration of the individual calculations in the manufacture of the diffuser ρτοϊΠβ for optimal flow »Other methods for generating similar profiles can also be used * A, Jiomenkiatux:

The first diffuser channel is indicated by the cylindrical in coordinates T ₃ 13 "and 2. The corresponding average velocity components are If, V and W. The flow conditions outside the boundary layers in the vicinity of the wall are characterized by missing indices; the conditions within the boundary lines are indicated by the index B; the conditions on the wall are represented by the index W; the flow conditions at the inlet are given by indices. _; _-.... ■. ; \ -:, .., '-.-- - _{"J_:;;} V.

The flow properties are:

Pressure P; ■ -; -; "Γ.-ν.- ^:. ■ .."'■■; · ■ :;: '_ ■■ · ' ■ "'' - ■■ ~ ^:. ~ 'W: ν ^Γ -

Density P *

Temperature t, '·' ^

Bynamic viscosity p- .

Kinematic viscosity "V *

Thickness of boundary layer S -

Shear stress on the wall due to radial turbulence T _y Radial Mach number N4-

BATH ORIGINAL

Q0988S / Q561

D. Equations of fluid mechanics:

Using the equations of Navier-Stokes and the retention of the mass in cylindrical coordinates is based on the assumption of a constant, compressible and syrametric axis Boundary-layer flow given the following integral equation for the quantity of motion:

WHERE

U- ■ ·

and

In the original extension of the well-known Buri method for two-dimensional, non-compressible flow becomes the following

0098 8 6/0581 bad original

? ■ -

derived from (JTe ic linn sr (l):

- Jk f

tHr-ί > !? + Se "- '- fir ⁵ - , .075 / = .017

-Γ —-fi -'- V-

v. {d _v

Hei KiufUsunc: the definition of Tj in iiteiclmnii (2) arises a linear '"equation: first order in Y-:

dr

Yr = .0 / 7

The integration of equation (3) gives for

009886 / 05SI

BATH

ir "~

And K is a constant of integration. C. Diffuser profile:

The solution of equation (4) can be achieved by U, V and G as functions of r and by the necessary integration. The constant K is obtained by _{prescribing a certain value of 7 r} for r = r.

For example, let U be given by:

-Ι

I (conservation of mass)

_r L-

Where L is the distance between the diffuser walls, V is given by:

(free turbulence)

X ίϋ -

G can be taken from FIG. With a certain r > is generally approximation method T ^. determined for the special L. Using the values of jBuri, TJ is limited to the range:

0098 86/0 561

Tr

- .0033 "a -.06

(Standstill) (replacement *) "

The diffuser profile shown in FIG. 7 is achieved if the wall distance L in area 18 is determined according to the following equation : ""'

W * r-

(5)

From the NACA Technical Note 1426

tan I =

and

.ta «.._ 4i = -ψ

r _o1 s radius of constriction 21

L ₂₁ = distance from the wall during reconciliation 21

The dimensions r ₂₁ and L-. are determined by the desired execution conditions. of the diffuser is determined by the mass flow rate and the pressure ratio.

. - The Di / ftuaorprofil imtBevreich 19 can also * according to the NACA

"Fe, ehnlcaI J?

182 & 227

The value T can vary between 4 and 10 degrees.

The precalculation of L in area 19 is finished when TL from equation (4) reaches the impending separation value of almost -0.055. The wall clearance in region 20 is "calculated if the expression Ty = -0.055 is kept constant in order to maintain the impending detachment, unfavorable, boundary layer of the diffuser discharge.

The course of the profile calculation can be, for example using the following references.

1. H. Schlichting, "Boundary Layer Theory," McGraw-Hill, 1955.

2. S. Pai> "Viscous Flow Theory", Van Nostrand, 1957.

3. NACA Technical Note 1426, 1947.

Other computational methods could be used to obtain the in Figure 7 generally shown shape of a diffuser without Detachment and obtained without guide vanes. The diffuser flow could also be discontinuous or asymmetrical. The boundary layers could be both laminar and turbulent. The flow could be axial like the exit from an axial turbine or at some intermediate angle with respect to the Wave 1.2 passed. .

^ ■ cölda

009886/0561

Claims (3)

P ATE NT ANW A LT E DipL-lng. MARTIN LIGHT PATENT LAWYERS LIGHT. HANSMANN ₁ HEiIMANN «Γ. REIN HO LD SGH MIDT SMONCHENI-THEITESIENSTIASSEJS iv ι w ^ .j_ 'ι * v t ■ u i'n ^: -. «Λ" ». · Dipi.-Wirfsch.-Ing. AXEL HANSMANN 41 Dipl-Phys. SEBASTIAN HERRMANN Monks, July 4th 196 YourZcifiwn. _; Unitr sign CATERPILLAR THACTpR CO., oan Leandro, California, V 3t. A. Patent application: "Diffuser without guide vanes ¹¹ Pat e nt to s ρ r ü c he: ίΐ.ί A diffuser passage in a fluid system, characterized in that it (16, 16 ') in its contours corresponds to the principle of the imminent separation of the boundary layer (Figures 1 to 3) 2. A diffuser passage in a fluid system, characterized in that it (16) at its entrance an area (18) of converging walls (to 21) has, that it thus reduces the flow turbulence that he is at it then a section (19) with diverging Walls up to a point (22) has that at this a state (25) is reached in which the boundary layer separation is imminent, and that a continued wall formation (20) the maintenance of a state (26, 27) serves for the imminent separation of the boundary layer up to the exit point of the diffuser. 009806/0661 - - < 3. A diffuser without guide vanes on the outlet side of a centrifugal compressor with the characteristics of Claim 2 and further characterized in that at the inlet the turbulence of the from the compressor (14, 15) coming river is diminished. ^ΒΑΰ on, 009886/0561