RU2086774C1 - Reaction turbine for multi-phase working medium - Google Patents

Abstract

FIELD: gas and steam turbomachines for driving electric generators, compressors and pumps. SUBSTANCE: reaction turbine has casing and rotor whose hollow shaft carries working wheel made in the form of disc provided with system of radial curvilinear passages brought in communication with interior of shaft; outlet sections of passages bent tangentially relative to circle of working wheel are provided with Laval nozzles and additional discharge passages with drain holes closed by check valves; inlet of additional discharge passage is located before Laval nozzle. Condensate separated from working flow in course of motion via curvilinear radial passages is accumulated in discharge passages and is discharged to collecting chamber through drain holes upon accumulation of definite amount. EFFECT: enhanced efficiency. 6 cl, 3 dwg

Description

 The invention relates to the field of turbine construction, mainly to turbines operating on "raw" natural gas, and can be used in gas and steam turbomachines to drive electric generators, compressors, pumps.

 It is known to use axial turbines to drive natural gas powered electric motors that are installed directly in a well or in a transport pipeline [1] However, when operating on a "raw", i.e. natural gas not drained and not cleaned of liquid and solid particles, condensate droplets and solid particles cause erosion of the turbine blades and often lead to their mechanical destruction.

 Due to the noted drawback, the indicated technical solution has not found industrial application, and in practice the axial turbines operate as part of gas expander units that have undergone primary processing at the plant or at the consumer at the gas distribution point.

 Known dual-flow radial-axial turbines containing a radial nozzle apparatus with a flow separator and axial blade crowns between which there is a chamber with a separating ridge on the rotor, while the cavity of the flow separator communicates with the cavity of the chamber by means of an annular gap provided with side visors bent into the cavity of the separator [2] The specified device provides for the removal of condensate in front of the working crowns due to the presence of a hollow flow separator in communication with the chamber cavity.

 The disadvantages of the known device is the complexity of its design and insufficiently high separation efficiency. In addition, this device provides efficient operation only when using wet steam as a working fluid.

 When working on "raw" gas, the device will not provide an effective separation of condensate and solid particles, since the conditions for their directed separation are not created.

 Jet turbines are also known, comprising a housing in which a working element of the Segner wheel type is located with tangentially mounted nozzles [3]. The specified turbine design when operating on a two-phase flow provides efficient condensate separation due to the design of the impeller. Moreover, this solution does not provide for the removal of condensate, as a result of which the separated condensate in the form of droplets is reflected from one turbine blade to another, causing their erosion. Moreover, in the process of their repeated recycling, droplets are enlarged and accumulated in the cavity of the impeller, designed in the form of a hollow drum, closed from the ends by two disks.

Of the known turbines, the closest to the proposed one is a jet turbine for a two-phase flow of a working medium, comprising a housing and a rotor, on the hollow shaft of which an impeller is installed in the form of a system of curved radial channels communicating with the shaft cavity, in the output sections of which are bent in the tangential direction relative to impeller circumference, Laval nozzles installed [4]
However, the indicated device also does not organize the removal of the separated condensate at a constructive level, as a result of which the walls of the channels and in particular the nozzles installed in their outlet sections are eroded.

 The basis of the present invention is the creation of a jet turbine design, providing when working on natural ("raw") gas, reducing the degree of erosion of the walls of the nozzles and, thus, increasing the reliability of the turbine.

 The problem is solved in that in a jet turbine for a multiphase working fluid containing a housing and a rotor, on the hollow shaft of which at least one impeller is installed in the form of a disk with a system of curved radial channels communicating with the cavity of the shaft, in the output sections of which bent in a tangential direction relative to the circumference of the impeller installed Laval nozzle.

 According to the invention, the outlet portions of the channels have additional outlet channels connected to them with drain holes blocked by non-return valves, the entrance to the additional outlet channel being located in front of the Laval nozzle.

 It is advisable to enter the additional bypass channel in the rear wall of the main channel.

 Preferably, the distance from the axis of the main channel to the entrance to the additional outlet channel should be no more than 3 and not less than 1.5 of the reduced diameter of the main channel.

In a preferred embodiment:
the check valve may be made in the form of a spool valve located at the plugged end of the outlet channel;
longitudinal grooves are made on the rear walls of the branch channels;
flow turbulators are installed on the inner surface of the outlet sections of the main channels.

 In FIG. 1 shows a General view of the device; in FIG. 2, section AA in FIG. one; in FIG. 3 section BB in FIG. 2.

 The turbine contains a housing 1, in which the rotor 2 is located, on the hollow shaft 3 of which one or several disks 4 with curved radial channels 5 are installed for the passage of the working fluid to nozzles 6 having the form of Laval nozzles and installed on the output sections of the 7 channels tangentially relative to the circumference of the disks 4.

 The channels 5 have additional outlet channels 8 with drain holes 9 and spring-loaded spool valves 10 to divert the separated liquid into the collection chamber 11. The inlet 12 to the additional outlet channel is made in the rear wall of the main channel in front of the Laval nozzle.

 Moreover, longitudinal grooves 13 are made on the rear walls of the branch channels 8, forming paths for moving the separated liquid. On the inner surface of the output sections 7 of the main channels installed flow turbulators 14, made, for example, in the form of knives or ring scallops.

 The collection chamber 11 is equipped with mechanical seals 15, eliminating leakage of condensate into the gas cavity of the turbine.

 The operation of the turbine is based on the reactive action of the gas stream exiting the nozzles 6. The working fluid in the form of wet steam or "raw" natural gas is supplied under pressure through the hollow shaft 3 into the radial channels 5 and is ejected through the nozzle 6, causing the rotor 2 to rotate.

 Condensate contained in natural gas or wet steam is discarded under the action of centrifugal forces to the rear convex walls of channels 5 and, entering through additional input channels 8 through input 12, moves in the form of a film along the paths formed by grooves 13 into the muffled ends of the drain channels 8.

 Upon reaching a certain amount of condensate, a force is created sufficient to overcome the force of the spring pressing the spool valve 10, as a result of which the valve 10 opens and the condensate is discharged through the drain holes 9 into the collection chamber 11.

 After draining the condensate, the valve 10 closes, and the process of accumulating the separated condensate is repeated.

 Similarly, separation and discharge through drain holes 9 occur together with condensate of rock particles (sand) in the presence of them in natural gas.

 The purified gas or dry steam is sent to the nozzle 6.

 It was experimentally established that the optimal conditions for condensate drainage will be provided if the following condition is met: the distance from the axis of the main channel to the entrance to the additional bypass channel 8 should be no more than 3 and not less than 1.5 of the reduced diameter of the main channel 5.

 With a low value of the humidity of the initial working fluid, the gas flow directed to the nozzles may contain a certain amount of unseparated and unremoved condensate, which will have an erosive effect on the nozzles. To reduce the erosive effect of the flow on the nozzle walls, on the inner surface of the outlet sections 7 of the main channels 5, knives or ring combs are placed in front of the nozzles 6, which act as turbulators of the flow and ensure its homogenization, i.e. dispersion to a "foggy" state. At the same time, the moment of momentum of the jet leaving the nozzle increases, i.e. An increase in turbine power is achieved.

 The proposed design of the turbine due to the increased wear-resistant characteristics can find application in the fields of gas condensate fields as a turbo throttle to reduce pressure while at the same time obtaining electric pressure for local needs and external consumption due to the used differential pressure.

Claims (6)

 1. A jet turbine for a multiphase working fluid, comprising a housing and a rotor, on the hollow shaft of which at least one impeller is installed in the form of a disk with a system of curved radial channels communicating with the shaft cavity, in the output sections of which are bent in a tangential direction relative to the circumference the impeller, Laval nozzles are installed, characterized in that the output sections of the channels have additional outlet channels in communication with them with drain holes covered by valves, the entrance to an additional bypass channel is located in front of the Laval nozzle.  2. The turbine according to claim 1, characterized in that the entrance to the additional bypass channel is made in the rear wall of the main channel.  3. The turbine according to claims 1 and 2, characterized in that the entrance to the additional bypass channel is made at a distance from the axis of the main channel of not more than 3 and not less than 1.5 of the reduced diameter of the main channel.  4. The turbine according to claim 1, characterized in that the check valve is made in the form of a spool valve located at the plugged end of the outlet channel.  5. The turbine according to claim 1, characterized in that longitudinal grooves are made on the rear walls of the outlet channels.  6. The turbine according to claim 1, characterized in that on the inner surface of the output sections of the main channels placed flow turbulators.

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