JPS6282203A - Dual-phase multiple stage nozzle - Google Patents

Abstract

PURPOSE:To atomize a liquid drop, by forming an annular passage between a senior nozzle and a jonior nozzle, and opening the annular passage into a divergent cylindrical portion of a nozzle passage. CONSTITUTION:An annular passage 4 is formed between a senior nozzle 5 and a junior nozzle 3. The annular passage 4 is opened into a junction between divergent cylindrical portions 3c and 5c of a nozzle passage. A pressurized hot water flowing from an inlet 3a is partially fed through the annular passage 4, and is injected from the junction between the divergent cylindrical portions 3c and 5c to accelerate tthe hot water forced against an inner wall of the divergent cylindrical portions. Accordingly, it is possible to atomize the liquid drop deposited on the inner wall.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention provides a nozzle ζ that efficiently converts the energy of a gas-liquid two-phase fluid flowing into a turbine into velocity energy.
Regarding this.

[Prior art and its problems]

Total flow turbines (gas-liquid two-phase flow turbines) are driven by high-pressure, high-temperature liquids and pressurized hot water, and their energy is effectively used in geothermal and nuclear power plants. The turbine is rotated by applying a force to it using pressurized hot water (this is done through a nozzle).

It is necessary to effectively convert the energy of pressurized water into velocity energy and flow it into the blade chamber. Conventionally, the shape of the nozzle is as shown in the cross-sectional view of FIG.
i (small cross-sectional area part) and a flow path tc that widens toward the end from the throat part tb.
It is known to have a flow path formed by. When hot water flows in from the inlet la of such a nozzle l, the hot water flashes near the throat tb and rapidly expands, converting a part of the hot water into steam, rapidly increasing its speed, and forming a tube that expands toward the end. A gas-liquid two-phase flow is ejected from the % IC flow. The steam flow at this time presses the hot water that did not evaporate and spread out against the wall surface of the cylindrical channel 1c, and flows through the space between them. Note that a portion of the hot water pressed against the wall surface becomes water droplets and is carried over by the steam flow. However, most of the hot water is decelerated by friction with the nozzle wall and is therefore ejected from the nozzle at a much slower velocity than the steam flow.

FIG. 4 is a graph showing the velocity distribution of a two-phase flow consisting of steam and hot water, with the nozzle outlet diameter CD plotted on the vertical axis and the velocity plotted on the horizontal axis. As is clear from the figure, the velocity near the nozzle wall is slow, and as it moves away from the wall, the velocity increases rapidly and becomes approximately uniform.

By the way, in order to obtain rotational power by spraying the fluid ejected from the nozzle onto the rotor blade, the angle at which the fluid flows into the rotor blade according to the flow velocity of the fluid ejected from the nozzle, that is, the inflow angle, needs to be an optimal angle.

However, as mentioned above, when the speeds of steam and hot water flowing near the nozzle wall are significantly different, it is important to take a predetermined inlet angle that corresponds to one speed, for example, the speed of the steam flow, and the other speed, that is, the heat flow. A predetermined inflow angle corresponding to the water velocity cannot be obtained. For this reason, there is a drawback that the rotational power obtained by the rotary turbine is reduced, and the performance of the total flow turbine is deteriorated.

[Purpose of the invention]

The present invention aims to provide a two-phase flow multi-stage nozzle that can bring the flow velocity of liquid close to the flow velocity of gas when flowing in the nozzle as a gas-liquid two-phase flow. purpose.

[Summary of the invention]

According to the present invention, the nozzle has a flow path in which a cylindrical portion, a tapered cylindrical portion, and a cylindrical portion that widen toward the end are successively connected from the inlet to the exit side, and A family nozzle, which is provided at a vertically symmetrical position of the inlet 1111 of the cylindrical partial flow path and has a groove portion with an opening surface toward the flow path center line, is connected to a cylindrical portion and a tapered columnar portion. It has an outer shape formed by the circular shape, and has a flow path formed by having an inlet in its longitudinal center as a tapered cylindrical part, and then a cylindrical part and a cylindrical part that widens at the end, which are successively connected. A child nozzle is provided at a vertically symmetrical position on the inlet side of the columnar part and has a fixing protrusion that can fit into a groove provided in the group nozzle, and the fixing protrusion is provided in the groove. When the parent and child parts are fitted together and the parent and child parts are combined, the flow path center line of the group nozzle and the flow path center line of the child nozzle are aligned, and the cylindrical part disposed on the aforementioned nozzle and the tapered cylindrical part are aligned. An annular flow path having a predetermined interval is formed between an inner peripheral surface of the flow path formed by the cylindrical portion and an outer peripheral surface formed by the cylindrical portion and the tapered cylindrical portion of the child nozzle. This is achieved by configuring the flow path to open into the diverging flow path just before the diverging section of the flow path of the group nozzle begins.

[Embodiments of the invention]

Embodiments to which the present invention is applied will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the two-phase flow multi-stage nozzle of the example (BB@ plane view in FIG. 2, which will be described later), and FIG.
It is an A side view. In FIGS. 1 and 2, the same parts as those in the conventional example shown in FIG. 3 are given the same reference numerals.

In FIG. 1jg2, the two-phase flow multi-stage nozzle 10 consists of a child nozzle 3 and a family nozzle 5. The child nozzle 3 has an inlet 3a as a nozzle formed into a tapered cylindrical shape, a cylindrical throat part 3b (minimum cross-sectional area part), and a throat part 3b.
The outer shape of the child nozzle 3 is formed by a columnar part and a tapered columnar part, and the nozzle inlet 3all has a vertically symmetrical position. A key-shaped fixing protrusion @3a is provided at.

The group nozzle 5 is located from the inlet side of the child nozzle: a cylindrical portion into which a holder can be inserted and a tapered cylindrical portion, and is located on an extension of the channel portion 3C formed in a cylindrical shape that widens at the end of the child nozzle 3. The flow path includes a flow path consisting of a cylindrical portion 5C that widens toward the end, and a groove portion 5a in which the fixing protrusion 3d fits into a vertically symmetrical position of the cylindrical portion of the flow path.

In addition, compared to the inner diameter of the flow path formed by the cylindrical portion of the group nozzle 5 and the tapered cylindrical portion, the outer diameter of the portion corresponding to each of the group nozzles 5 on the outer peripheral surface of the child nozzle is a predetermined value. (
This value is determined from the pressure, temperature, amount, etc. of the hot water being sent in).

Therefore, the child nozzle 3 is inserted into the group nozzle 5 configured as described above from the inlet side, and the child nozzle 3 is inserted into the groove 5a.
By fitting the fixing protrusion 3d, the inner peripheral surface formed by the cylindrical part of the flow path of the group nozzle 5 and the tapered cylindrical part and the columnar part of the child nozzle and the tapered columnar part are formed. A gap of a predetermined size, that is, an annular flow path is formed between the outer peripheral surface and the outer peripheral surface. Also, like this, group nozzle 5 and child nozzle 3
When assembled, the flow path center line of group nozzle 5 and the flow path center line of child nozzle 3 coincide.

With this configuration, the two-phase flow multi-stage node A' (ru 1
The pressurized hot water flowing in from the inlet 3a of 0 flows along the wall of the prior art and 50 at a speed considerably slower than the speed of steam, and the steam flows quickly between the hot water pressed against this wall. flowing at speed. However, a part of the hot water flowing into the two-phase flow multi-stage nozzle passes through the annular flow path 4 and is ejected from the opening surface 4a of the connecting part between the cylindrical flow path 3C and the flow path 5C, which expands toward the end and becomes cylindrical. The hot water pressed against the P-3 wall of the flow path 5C is accelerated, the water droplets are atomized, the speed is increased, and they are ejected from the nozzle.

Therefore, the pressurized hot water flowing into the two-phase flow multi-stage nozzle 10 is ejected as a high-speed steam flow and a flow of accelerated droplets approaching the steam flow velocity, and the steam and droplets are combined. Since the flow velocity distribution of the two-phase flow consisting of the two-phase flow is substantially uniform, the inflow angle to the rotor blade can be set to an optimal predetermined angle.

In this embodiment, the fluid flowing into the two-phase flow multi-stage nozzle has been described as pressurized hot water which is a liquid, but the same effect can be obtained even if the fluid is pressurized hot water containing steam.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the two-phase flow multi-stage nozzle is composed of two parts, the group nozzle and the child nozzle, and includes a part of the inner peripheral surface of the parent nozzle flow path and an outer peripheral surface of the child nozzle. By forming an annular flow path with a predetermined interval between the nozzle flow path and the nozzle flow path, accelerated hot water is ejected from the annular flow path that opens in the middle of the cylindrical part that widens toward the end of the nozzle flow path. This makes it possible to refine the low-velocity droplet flow that spreads toward the end and flows along the inner peripheral surface of the cylindrical channel.

It has become possible to increase the flow velocity and bring it closer to the velocity of the steam flow flowing through the center of the channel. As a result, the flow velocity distribution of the two-phase flow consisting of steam and droplets near the nozzle exit is averaged at a high position, making it possible to take the optimal inflow angle to the rotor blade, improving total flow turbine performance. It is possible to obtain the effect of significantly improving the

[Brief explanation of drawings]

FIG. 1 is a sectional view of a two-phase flow multi-stage nozzle according to an embodiment of the present invention, FIG. 2 is a side view taken along line A-A in FIG. 1, FIG. 3 is a sectional view of a conventional nozzle, and FIG. 1 is a diagram showing the velocity A2 near the exit of a conventional multi-stage nozzle. 1: Nozzle, 3a: Inlet, 3b = Throat, 3c, 5c
: cylindrical channel with a widening end, 4: annular channel, 10: two-phase flow multi-stage nozzle. ? Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A flow path formed by successively connecting a cylindrical portion, a tapered cylindrical portion, and a widening cylindrical portion from the inlet toward the outlet, and vertically symmetrical positions on the inlet side of the cylindrical partial flow path. a parent nozzle which is provided in the main nozzle and has a groove having an opening face toward the center line of the flow path, and has an external shape formed by a series of cylindrical portions and tapered columnar portions, and has a longitudinal center thereof. a flow path formed by a tapered cylindrical part on the inlet side, and a cylindrical part and a cylindrical part that widens toward the end in sequence, and is provided at vertically symmetrical positions on the inlet side of the cylindrical part, and a child nozzle having a fixed protrusion that can be fitted into a groove provided in the parent nozzle, and when the fixed protrusion is fitted into the groove and the parent and child are combined, the parent nozzle The flow path center line of the child nozzle coincides with the flow path center line of the child nozzle, and the flow path inner peripheral surface formed by the cylindrical portion and the tapered cylindrical portion arranged in the parent nozzle and the child nozzle An annular flow path having a predetermined interval is formed between the outer circumferential surface formed by the cylindrical portion and the tapered columnar portion, and the annular flow path is located immediately before the end widening portion of the flow path of the parent nozzle begins. A two-phase flow multi-stage nozzle characterized in that it is configured to open toward a flow path that widens toward the end.