US1908066A - Nozzle for gas turbines - Google Patents

Description

May 9, 1933. M. SEDLMEIR NOZZLE FOR GAS TURBINES Filed Aug. 7, 1930 2 Sheets-Sheet l bye/7 for fiflorne MW 1 1 a 5 5:: I 5 K2 1 \1. u I .w m F 9 V Y I 7// 2 1 1 m.

2 Sheets-Sheet 2 Filed Aug. 7, 1930 Patented May 9, 1933 UNITED STATES.

mcnanr. ssnnmnra, or mutnmm on rnn-nnna, GERMANY, assxenony'ro nonz- PATENT OFFICE wan'rn .GAS roasmn so, clean rnancisco, caLironnrah oonronarion or y DELAWARE INOZZLE 203 Gas renames application meaaugun 7, isaojsmarno. 473,142, and in Germany Airgun 23,1929.

My invention relates to nozzlesfor con ducting a fluid medium of such high temperature as tonecessitate the employment of a cooling jacket about such nozzles; and more particularlyto nozzles of the expansion type forconducting to a turbine rotor the gases generated in the explosion chamber of an explosion turbine. y

It is one of the objects of the present inventionto simplify the manufacture of a nozzle of the above-mentioned type and to provide a nozzle of superior efliciency and reliability. It is also an objectof the invention to provide a sectional nozzlewhose central por- 157 tion is formed of pressed metal so that machining thereof is rendered unnecessary while at the same time greater accuracy is secured. Other objects and advantages will appear from the following description and the features of novelty will be pointed out in the claims.

In the acompanying drawings is shown by way of example a preferred embodiment of the invention. In said drawings, F i 1 is a longitudinal section through the nozz e along the line I-I of Fig. 2; Fig. 2 is a view of the nozzle in elevation from the outlet end thereof; Figs. 3, 4 and 5 represent transverse sections ta ken along the lines IIIIII, IV-IV,

and V-V, respectively, of Fi 1- Fig. 6 is a section along the line VI-V of Fig. 1 and shows also the adjoining turbine parts; and Fig. 7 shows my im roved nozzle 1n association with an explosion chamber and the rotor of an explosion turbine.

My improved nozzle is of particular advantage in combustion gas turbines and will be described in connection with such an apparatus.

a understood in the art, gases under high temrlture and pressure may be generated within combustion chambers 1 (of which onl one is indicated in Fig. 7 of the drawings) orming part of a gas turbine, such as an explosion turbine of the constant volume type. In this latter tvne of turbine, the explosion chambers are periodically charged with an explosive mixture which is exploded therein,

b means not shown on the drawings, the nozzle valve 2 of each chamber being periodical- In such turbines, as is now well 1y opened to permit the ases to discharge from the outlet end 3 oft e chamberinto a nozzle channel 4. From the latter the gases flow into the gas nozzle by which they are directed against the rotor of a turbine, such rotor comprising,forexample, two rows of blades 5, 6, between which are located stationary reversing bladesi'.

The gases entering the nozzle are of very high temperature, so thatthe nozzlemust be providedwith a cooling jacket to prevent destruction thereof. With gas nozzles of the de Laval type, wherein the nozzle first dimin+ ishes in cross-section from the inlet end thereof .to the throat section, and then increases in cross-section from such throat toward the outlet end, the latter being preferably curved to corres 0nd to. the circle alongwhich the rotor bla es lie, the provision of such cooling jacket presents many. serious difii'culties.

When the nozzle body isformedas a sin 1e casting with as much as possible of the j ac et cast integral with it, thedangerlexists, particularly with the larger and more compllcated castings, that all of the core is not removed, so that local overheating and burning out is liable to occur when the nozzle is in use. It is also very d-ifiicult to machine the inner wallsof the nozzle castingalong which. the hot gases flow so as to reduce friction losses. y l 1 i i In accordance with the presentzinvention, I overcomemthese difficulties and gain certain important advantages by forming the nozzle inlet and outlet sections as. separate parts, while the central section, whose form determinesthe velocity and pressure rela tions of the gas fiowingtherethrou h, and is therefore the most critical part of t e nozzle,.I form of pressed metal, so that it possesses a smooth "interior. surface and thus reduces the energy losses due to friction.-

of the nozzle, such as the cross-sectional area of the throat portion, can be attained thanin casting1 As s own in the drawings, the nozzle comprises an inlet section 8, an outlet section 9, a

: are provided with jacket sections 16, 17

which extend in the direction of the nozzle axis and are connected bywelding, as shown at: 33, 34, with a middlejacket or shell, so

that there is formed a cooling space 19 which,

extends for substantiallythe whole length of the as passageway 18.0f the nozzle.q.The :0 mid lecooling'jac et section, may, likethe middle section of-the nozzle body, be formedofa U-shaped part 20 and a coverplate 23 welded to the and 5). $5 .The coolin enter the coo 'ng space 19 at the outlet end of the nozzle through a conduct 24 (Fig. .6)

andiswithdrawn by conduit25 (Fig. l) atthe inlet end of the nozzle.

80 o The end sections 8 and 9 of the nozzle may be of cast steel, while the middle portion may be made of ametal or alloy welded with steel, such as mckel-copper-iron alloys or wrought iron plate. Because of 85 the efiicient cooling of the nozzlebody by the aid of thecooling jacket, the inner walls of the nozzle need be only strong enough-to withstand the pressure of the gases flowing through the nozzle, so that wrought iron platelofi'ers a very satisfactory structural materia. I r

The inlet 26 of the nozzle is -of circular form, the inlet section rapidly diminishing in cross-section to the throat 27 which is inthe re 'on ofjthe welding seam 10. From the throat27 the nozzle gradually increases in cross-section tothe. sector-shaped outlet 28. The shorter or upper nozzle wall is referably cut away in advance of the outet,'as'shown'at 35, in orderto avoid the presence oftoo much metal between the cool ing space 19 and the inner surface of such wall. :The .end castings 8 and. 9 are provided with flanges 29 and 30,-respectively, having openings 31 and 32to receive fastening means whereby the nozzle may befixed to the turbine frame. i Variations may be resorted to withinthe scope of the-appended claims withoutdearting. from-the spirit of the invention. or instance; the parts 12 and -20-need not be made-of U-formbut may be given other shapes.

I claim: 7

1. A jacketed nozzle suitable for use with part 20 at 21, 22 (Figs. 3, 4

medium, such as water, may

adapted to beexplosion chambers, preferably in gas turbines, comprising separately cast inlet and outlet sections and a middle section formed of sheet metal with a smooth surface and connected with the inlet and outlet sections along lines transverse to the axis of the nozzle, the inlet section terminating'in the vicinity of the throat of the nozzle, the inlet and outlet sections having jackets integral therewith, and a jacket of sheet metal surrounding the middle section and connected with the first mentioned jackets.

2. A nozzle suitable for use in explosion gas turbines, comprisinga body portion having separately formed'mlet, outlet and middle sections, saidv middle section-comprising a sheet-metal part of U-shape and a closure plate connected therewith, and a cooling jacket about said sections.

3. A nozzle suitable for use in explosion gas turbines, comprising a body portion having separately formed inlet, outlet'and middle sections and a cooling jacket about said sections, the portion of said jacket about the middle section comprising a sheet-metal part of U-shape and a closure plate connected therewith. I

7 MICHAEL SEDLMEIR.

Images