JP6042061B2 - Spray nozzle, fluid atomizer using the spray nozzle - Google Patents

Description

  The present invention relates to a spray nozzle that mixes and sprays a gas and a liquid, and a fluid atomization apparatus using the spray nozzle.

When liquefied natural gas (hereinafter referred to as “LNG”) is vaporized and supplied as city gas, the amount of heat is adjusted. In recent years, the import of LNG rich in methane components has increased, and in many cases the heat is increased for city gas. The calorific value is adjusted by mixing natural gas with a calorific value adjusting agent such as liquefied petroleum gas (hereinafter referred to as “LPG”).
As such a calorific value adjusting method, for example, Japanese Patent Laid-Open No. 63-265994 (Patent Document 1) supplies vaporized natural gas to a venturi-type liquid / gas mixer, and generates a high-speed flow and low pressure generated in a venturi pipe. A technique for atomizing, evaporating, and mixing a calorific value adjusting agent supplied in a liquid state to a venturi tube is disclosed.

Japanese Patent Laid-Open No. 53-131328 (Patent Document 2) relating to a fuel vaporizer for an internal combustion engine, although not a city gas heat increasing device, discloses a technique for providing a throttle member that can move in the flow path direction in a venturi pipe. Is disclosed.
Further, JP-A-8-75621 (Patent Document 3) relates to a constant flow rate sampling device, in which a spindle-shaped core is fixed in a tube serving as a gas flow path, and a throat portion disposed outside the core is pulsed. A technique for changing a cross-sectional area of a flow path by moving it in the flow path direction by a motor is disclosed.
Japanese Utility Model Laid-Open No. 56-41210 (Patent Document 4) and Japanese Patent Application Laid-Open No. 4-248414 (Patent Document 5) relate to a flow rate measurement control device, and a circular cross-sectional area is provided in the flow direction in the throat portion of the Venturi tube. A technique is disclosed in which a movable body having a surface that changes along the line is disposed, and the movable body is driven by a motor disposed in a flow path.
Furthermore, JP 2011-56400 A (Patent Document 6) relates to a fluid mixing method, and a branch channel having a small diameter portion whose channel cross section is smaller than that of the main channel is provided by branching from the main channel. The flow rate of the first fluid that flows through the small-diameter portion of the branch flow path by arranging the outlet side in the main flow path, providing the second fluid supply section at or near the small-diameter section of the branch flow path, and adjusting the flow rate of the main flow path Is a technique for maintaining the flow rate required for mixing the first fluid and the second fluid.

JP 63-265994 A JP-A-53-131328 JP-A-8-75621 Japanese Utility Model Publication No. 56-41210 JP-A-4-248414 JP 2011-56400 A

The flow rate of natural gas varies according to the city gas demand. A value obtained by dividing the operation flow rate by the rated flow rate is referred to as a turndown ratio. However, when the turndown ratio of natural gas is low, it may be operated at about 1/20.
On the other hand, when the flow rate of the Venturi tube decreases, the flow velocity and the low pressure generation effect decrease. Like the one disclosed in Patent Document 1, there is a problem that it is impossible to cope with a large change in the amount of city gas demand if the sectional area of the venturi tube throat is constant.
Venturi pipes, etc. are designed based on the rated flow rate, but when the natural gas turndown ratio is low, the flow rate of the venturi section decreases, so the LPG added as a calorie regulator is sufficiently vaporized with natural gas A liquid dripping phenomenon occurs in which the liquid is accumulated at the bottom of the tube without being mixed. If this phenomenon occurs, it will interfere with the production of city gas.
The turndown ratio of natural gas that can be vaporized and mixed by the venturi tube is about 1/1 to 1/5. For this reason, when the technique of Patent Document 1 is used as an application destination with a large flow rate fluctuation range, it is necessary to prepare venturi pipes having different sizes according to the flow rate range, which causes problems such as complication of the apparatus.

In this regard, in the technique described in Patent Document 2, even if the flow rate of the air passing through the venturi pipe varies, the axial position of the throttle member is changed so as to cope with it.
However, Patent Document 2 does not disclose a driving method for moving the aperture member in the axial direction. Further, if the drive source is outside the flow path, the drive shaft penetrates outside the flow path, and the frequently moving surface is sealed. Therefore, there is a possibility that the fluid may leak from this surface, and there is a concern about safety when the fluid is flammable or dangerous.
Also in Patent Document 3, since the throat portion disposed outside the spindle core is moved in the direction of the flow path, it is possible to cope with fluctuations in the gas flow rate, but the drive section is outside the flow path. As in the case of Patent Document 2, the drive mechanism penetrates the inside and outside of the flow path, and there is a problem of sealing performance on the movable surface (sliding surface).

Similarly, in Patent Documents 4 and 5, although it is possible to cope with fluctuations in the gas flow rate, a motor as a drive source is disposed in the gas flow path, so that the structure becomes complicated. Considering the inflow of fluid into the motor unit that requires driving energy, there is a problem that it is difficult to apply to fluids that are flammable or corrosive.
Furthermore, in the one disclosed in Patent Document 5, the “flow rate” is controlled based on the pressure and temperature. However, what is important from the viewpoint of mixing the fluid is the throat of the venturi tube in accordance with the fluctuation of the flow rate. This is to control the flow velocity of the part, and such control is not possible with the one of Patent Document 5.

The one disclosed in Patent Document 6 is intended to solve these problems, and can reliably obtain a high mixing effect over a wide flow rate range, and does not require a movable part such as a movable body. Therefore, the driving unit for driving the movable unit is not required, the structure can be simplified, and the present invention can be applied to a flammable or corrosive fluid.
In this fluid mixing apparatus, the gas and the liquid are mixed inside the branch pipe or in the vicinity of the outlet, but the liquid is torn by the speed difference between the gas and the liquid, and atomization is promoted. However, when conditions such as the flow rate are severe, there is a concern that the liquid does not necessarily atomize and a dripping phenomenon may occur. That is, in the fluid mixing device having a large rated flow rate, the diameters of the main flow pipe and the branch pipe are also large. The larger the diameter of the branch pipe, the smaller the interface area between the liquid phase and the gas phase relative to the flow path volume of the branch pipe (the contact area between the gas phase and the liquid phase). Atomization uses the action of tearing the liquid phase into the gas phase due to the shearing force caused by the difference in flow rate between the gas phase and the liquid phase, so the contact area between the gas phase and the liquid phase is relatively small. It will lead to performance degradation.
On the other hand, increasing the gas flow velocity in the branch pipe can improve the atomization performance, but since the pressure loss increases in proportion to the square of the flow velocity, it is not possible to increase the gas flow velocity in the branch pipe unnecessarily. could not.

  The present invention has been made in order to solve such problems, and has a simple structure, is applicable to fluids having flammability and corrosivity, and has a high effect of preventing dripping phenomenon and It is an object of the present invention to provide a fluid atomization apparatus using the spray nozzle.

(1) A spray nozzle according to the present invention includes an outer tube that receives a gas supply from a proximal end side and ejects gas toward a distal end side, and a parallel pipe line that is disposed in the outer tube in a direction coaxial with the outer tube. An inner pipe having an opening provided on the inner peripheral surface of the inner pipe to supply liquid to the inner pipe, and a wall provided in the inner pipe for partitioning the inside of the inner pipe in the flow direction. With members,
The wall member is provided on the downstream side of the liquid supply part to which the liquid is supplied by the liquid supply pipe in the inner pipe ,
The length in the flow path direction on the downstream side of the connection portion of the liquid supply pipe in the inner pipe is at least five times the flow path diameter of the inner pipe .

( 2 ) Further, in the above (1 ), the wall member is a plate-like member.

( 3 ) Further, in the above (1 ), the wall member is a tubular member.

( 4 ) A fluid atomization apparatus according to the present invention is a fluid atomization apparatus using the spray nozzle according to any one of (1) to ( 3 ) above, and a flow rate of gas supplied to the spray nozzle And a flow rate adjusting valve for adjusting the flow rate of the gas flowing in the spray nozzle based on the detection value of the flow rate detecting device.

According to the present invention, a high mixing effect can be reliably obtained over a wide flow rate range, and the effect of preventing the dripping phenomenon is high.
Further, since the wall member that divides the inner pipe in the flow direction is provided, the liquid film is formed on a plurality of divided wall surfaces, the liquid film surface area, that is, the gas-liquid contact area increases, and the nozzle diameter is large. The dripping phenomenon can be prevented and the atomization performance can be improved.
In addition, since a movable part such as a movable body is unnecessary and a drive part for driving the movable part is also unnecessary, the structure can be simplified.
Furthermore, since it is basically composed of only a pipe member, the degree of freedom in selecting a material is high, and it can be applied to a fluid having combustibility and corrosivity by selecting an appropriate material.

It is explanatory drawing of the spray nozzle which concerns on one embodiment of this invention. It is explanatory drawing which illustrates typically the flow pattern by the difference in the flow velocity of the liquid phase which flows in a horizontal pipe, and a gaseous phase. It is explanatory drawing of the spray nozzle which concerns on one embodiment of this invention, Comprising: It is a figure explaining the other aspect of a wall member especially. It is explanatory drawing of the venturi-type atomization apparatus as an example of use of the spray nozzle concerning one embodiment of the present invention. It is an enlarged view which expands and shows a part of FIG.

[Embodiment 1]
The spray nozzle 1 according to the present embodiment is a spray nozzle that mixes and sprays gas and liquid.
The properties and applications of the gas and liquid mixed by the spray nozzle 1 are not particularly limited. As an example, city gas is obtained by adding and mixing LPG (liquefied petroleum gas) (liquid) to natural gas (gas) vaporized LNG. May be mentioned.
Hereinafter, the spray nozzle of the first embodiment will be described mainly with reference to FIG. 1A is a cross-sectional view taken along the axial direction (fluid flow direction) of the spray nozzle 1, and FIG. 1B is a cross-sectional view taken along the line AA. In FIG. 1, white arrows indicate the direction of gas flow, and hatched arrows indicate the direction of liquid flow.
Further, in the present specification, as a term for specifying a part of a member disposed in a gas and / or liquid flow path, the tip refers to the downstream side in the flow direction of the air flow and liquid flow, and the base end refers to the air flow and liquid flow. The upstream side in the flow direction.

As shown in FIG. 1, the basic configuration of the spray nozzle 1 according to the present embodiment includes an outer tube 2 that receives supply of gas from the proximal end side and jets gas to the distal end side, and an outer tube in the outer tube 2. 2, an inner tube 3 disposed in the same direction as the axis 2, a liquid supply tube 4 that supplies liquid to the inner tube 3, and a wall member 5 that is provided in the inner tube 3 and partitions the inside of the inner tube 3 in the flow direction. It is equipped with.
Hereinafter, each configuration will be described in detail.

<Outer tube>
The outer tube 2 is supplied with gas from the base end side. As an aspect in which the outer tube 2 is supplied with gas, for example, when the outer tube 2 is arranged in a pipe through which gas flows, or a gas supply tube (not shown) that supplies gas to the proximal end side of the outer tube 2 May be connected to.

<Inner pipe>
The distal end portion of the inner tube 3 is disposed coaxially with the outer tube 2 and inside the outer tube 2 via the inner wall and space of the outer tube 2. The inner tube 3 receives liquid supply from the liquid supply tube 4 at the side thereof, and ejects liquid at the tip side. The ejection is not only when the liquid is ejected vigorously by the force from the inner side of the inner tube 3, but also when the liquid supplied to the tip of the inner tube 3 is caught in and discharged from the air flow outside the inner tube 3. including.
The cross-sectional shape of the inner tube 3 is not particularly limited, and may be a circle or a polygon. Further, a structure for giving a swirling flow to the fluid passing through the inner pipe 3, for example, swirling blades may be provided.
The member attached to the inside of the inner tube 3 may be detachable.
The inner tube 3 is fixed to the outer tube 2, but the fixing method is not particularly limited, and may be fixed by, for example, a stay (not shown).

The inner tube 3 is arranged coaxially with the outer tube 2, a part of the gas flowing through the outer tube 2 flows in, and the liquid supplied from the liquid supply tube 4 flows in a two-phase flow state.
Two-phase flow refers to a phenomenon in which two phases, for example, a liquid phase and a gas phase, are mixed and flow. Mist has very small water droplets in the air. This is a two-phase flow called a spray flow (mist flow), and the liquid phase is dispersed in the gas phase.
On the other hand, beer poured into a glass, for example, contains a lot of small carbon dioxide bubbles in the beer, but this form is a two-phase flow called bubble flow, The gas phase is dispersed in the phase. The droplets in the spray flow and the bubbles in the bubble flow are called dispersed phases, while the gas phase in the spray flow and the liquid phase in the bubble flow are called continuous phases.
In an open space such as the earth's atmosphere, the dispersed phase is normally dispersed almost uniformly in the continuous phase, and there is a homogeneous flow such as a spray flow or bubble flow. However, a two-phase flow that flows in a closed space such as in a pipe generates not only a homogeneous flow but also a non-uniform flow.

The flow form of the two-phase flow depends on the flow velocity of the gas phase and the liquid phase, and a phase diagram showing how the flow form is obtained by these is experimentally obtained.
FIG. 2 is a diagram schematically showing a flow pattern according to a difference in flow velocity between the liquid phase and the gas phase flowing in the horizontal pipe. The figure shown here is the one described in the book “Gas-liquid two-phase flow” (author: Yasuhiro Ueda, publisher: Yokendo). The liquid phase and the gas phase flowing in the horizontal pipe show the following flow modes depending on the difference in flow velocity. The liquid-phase and gas-phase flow rates are apparent flow rates obtained by dividing the gas-phase and liquid-phase flow rates by the cross-sectional area of the flow path, and are also referred to as superficial velocity. Hereinafter, the flow velocity in this specification refers to the superficial velocity.
The transition of the flow pattern due to the difference in the flow velocity of the gas phase is as follows.
(1) When the gas phase flow rate is slow When the liquid phase flow rate is slow, the liquid phase flows along the bottom surface of the pipe (stratified flow). On the other hand, when the flow velocity of the liquid phase is increased, a spiral flow or a bubble flow is generated.
(2) When the gas phase flow rate is slightly high When the gas phase flow rate becomes high, the gas-liquid interface undulates and becomes a wavy flow or slag flow.
(3) When the gas phase flow rate is high, when the gas phase flow rate is further increased, part of the liquid is scattered, the liquid phase is pushed toward the wall surface and flows as an annular liquid film along the tube wall, and the gas phase Becomes an annular flow or an annular spray flow that continuously flows in the center of the tube at a considerable flow rate.
Note that the flow mode may be affected by the piping posture, and the flow mode is partially different for vertical pipes and the like whose gravity direction is different from that of the horizontal pipe. However, when the gas-phase flow velocity is high, the flow velocity (inertial force) becomes more dominant than gravity, so the influence of the piping posture on the flow mode becomes small. That is, when the gas phase flow velocity is high, the flow becomes an annular flow or an annular spray flow regardless of the piping posture.

In the spray nozzle 1 of the present embodiment, when an annular spray flow is generated in the inner tube 3, the atomization of the liquid is promoted, and the mixing of the liquid and the gas is increased.
In order to generate the annular spray flow, although depending on the flow rate ratio between the liquid and the gas, the superficial velocity of the gas may be 10 m / s or more, more preferably 20 m / s or more. In addition, although the atomization effect of a liquid is acquired also in the state of an annular flow, the effect can be heightened more by setting it as an annular spray flow. On the contrary, when the gas flow velocity in the inner pipe 3 becomes small, the annular flow or the annular spray flow state cannot be maintained, and a transition is made to a flow state such as a wavy flow, a slag flow, or a bubble flow. In this case, the dispersibility and uniformity of the liquid phase in the inner tube 3 is deteriorated and the gas-liquid contact area is reduced, so that the atomization performance is lowered.

An experiment was conducted to investigate the relationship between the gas superficial velocity and the presence or absence of liquid sag. This will be described below.
The experimental conditions are as follows.
・ Gas: Natural gas ・ Liquid: LPG
・ Gas mass flow rate: Liquid mass flow rate = 1: About 0.1 to 0.2 (Table 1)
・ Gas mass flow rate: Liquid mass flow rate = 1: About 0.5 to 1.0 (Table 2)
-Method for confirming the presence or absence of dripping: It was confirmed by the difference in the surface temperature between the upper and lower surfaces of the LPG-added downstream pipe (horizontal pipe part) and the visualization part (sight glass) observation.
The experimental results are shown in Tables 1 and 2.

According to the results shown in Table 1, since the dripping phenomenon occurs when the superficial velocity of the gas is slow, it is understood that the superficial velocity of the gas should be 10 m / s or more.
In addition, according to the results shown in Table 2 in which the liquid flow rate with respect to the gas flow rate is higher than that in Table 1, it is understood that the superficial velocity of the gas should be 20 m / s or more.

As described above, the flow form of the two-phase flow depends on the flow rates of the gas phase and the liquid phase. Based on the flow rate of the liquid to be sprayed, it is desirable to determine the cross-sectional area of the flow path of the inner tube 3 so that a flow velocity at which an annular spray flow is generated in the inner tube 3 is obtained.
Further, it is desirable that the length of the inner pipe 3 in the flow path direction on the downstream side of the connection portion (liquid supply section) of the liquid supply pipe 4 is not less than five times the flow path diameter of the inner pipe 3. By setting the flow path length of the inner pipe 3 as described above, an annular spray flow is easily formed inside the inner pipe 3 when the gas flow path has a sufficient speed.

<Wall member>
The wall member 5 is a member that is provided on the downstream side of the connection part (liquid supply part) of the liquid supply pipe 4 in the inner pipe 3 and partitions the inside of the inner pipe in the flow path direction. The wall member 5 may be a flat plate as shown in FIG. 1, or may be formed of a tubular member 7 extending in the same direction as the inner tube 3 as shown in FIG. (Not shown) may be used. 3 is a view for explaining the spray nozzle 1 in which the wall member 7 is another embodiment, and FIG. 3A is a cross-sectional view along the axial direction (fluid flow direction) of the spray nozzle 1, and FIG. FIG. 2B is a front view of the spray nozzle 1. In addition, the same code | symbol is attached | subjected to the same part as FIG. Although FIG. 3 shows an example in which one tubular member 7 is arranged substantially coaxially with the inner tube 3, a plurality may be provided substantially coaxially, and FIG. As shown, they may be arranged in parallel to each other in the flow path direction.
The reason why the wall member 5 is provided is as follows.
When the flow rate of the gas phase flowing through the inner pipe 3 is large, the cross-sectional area of the inner pipe 3 needs to be increased. However, in a state in which the flow pattern in the inner tube 3 is an annular flow or an annular spray flow, the liquid phase flows in a liquid film form on the inner wall surface of the inner tube 3, and the cross-sectional area of the inner tube 3 is large. As shown, the interface area between the liquid phase and the gas phase relative to the flow path volume of the inner tube 3 (the contact area between the gas phase and the liquid phase) becomes relatively small. Atomization uses the action of tearing the liquid phase into the gas phase due to the shearing force caused by the difference in flow rate between the gas phase and the liquid phase, so the contact area between the gas phase and the liquid phase is relatively small. It will lead to performance degradation.
Therefore, by providing the wall member 5 that divides the inner pipe 3 in the flow direction, a liquid film that is a thin liquid phase flow is formed on the plurality of divided wall surfaces, and the liquid film surface area, that is, the gas-liquid contact area increases, Atomization performance is improved.

The operation of the spray nozzle 1 according to the present embodiment configured as described above will be described.
The gas is supplied from the proximal end side of the spray nozzle 1, and a part thereof flows into the inner tube 3. The liquid is supplied to the inner tube 3 through the liquid supply tube 4.

The liquid supplied to the inner tube 3 through the liquid supply tube 4 merges with the gas inside the inner tube 3 and flows through the inner tube 3 in a mixed phase.
As described above, the inner pipe 3 takes various flow forms depending on the flow velocity of the gas. A state in which the mixed flow state flowing through the inner tube 3 is an annular flow or an annular spray flow is preferable because the atomization of the liquid is most favorable, that is, the particle droplet diameter is reduced.

When the flow rate of the gas phase is a flow rate capable of forming an annular spray flow, the liquid supplied from the liquid supply pipe 4 flows while forming a liquid film on the inner wall surface of the inner tube 3 as an annular spray flow. Since the spray nozzle 1 of the present embodiment is provided with the wall member 5 inside the inner tube 3, a liquid film is formed on a plurality of wall surfaces, the liquid film surface area, that is, the gas-liquid contact area increases, Even when the flow rate is large, that is, when the diameter of the inner tube 3 is large, excellent atomization performance can be realized.
At the outlet portion of the inner tube 3, the liquid film formed on the inner wall of the inner tube 3 and the wall surface of the wall member 5 is ejected while maintaining the liquid film state in the tube axis direction of the inner tube 3. On both sides of the liquid film, there is a gas flow flowing through the inner tube 3 or a gas flow flowing through the outer tube 2. That is, the liquid film is in contact with the gas phase on both the inner and outer surfaces, and the liquid film is torn and atomized by the shearing force resulting from the difference in flow rate between the liquid film and the gas phase.

  In addition, it is preferable to maintain the gas phase flow velocity within a range in which the flow mode in the inner pipe 3 can maintain the annular flow or the annular spray flow, and conversely within this range, the gas phase velocity can be reduced (the gas phase side pressure is reduced). Small). In general, the gas phase apparent flow rate may be maintained at 10 m / s or more, preferably 20 m / s or more.

As described above, the spray nozzle 1 of the present embodiment has a simple structure, can be applied to a flammable or corrosive fluid, and has a high effect of preventing a dripping phenomenon.
In addition, since the wall member 5 is provided in the inner tube 3 so that the liquid film is formed on the plurality of wall surfaces, even if the flow rate of the gas phase is large and the diameter of the inner tube 3 is increased. Atomization performance is improved.
Since the liquid film in the inner pipe 3 is formed by a gas phase flow, it is not necessary to reduce the cross-sectional area of the liquid phase flow path for forming the liquid film, and the liquid phase flow path is simple and the cross-sectional area can be increased. The pressure loss on the side can be kept small.
Further, the gas-phase-side channel in the spray nozzle 1 has a substantially straight tube shape, and there is no obstacle, so the pressure loss is small.

  In the above embodiment, the position where the wall member 5 is provided is set on the downstream side of the liquid supply unit, but when the inner pipe 3 is divided into a plurality of flow paths by the wall member 5, If the liquid supply part which can supply a liquid is provided in each flow path, the wall member 5 may extend to the upstream of the liquid supply part. The liquid can be uniformly supplied to the respective sections divided by the wall member 5.

[Embodiment 2]
This embodiment shows an example of a atomization apparatus using the spray nozzle 1 as an example of use of the spray nozzle 1 of the present invention. The temperature is increased by adding LPG to natural gas obtained by vaporizing LNG. It is used when producing gas. Further, in the second embodiment, a venturi pipe 11 is installed in the main flow pipe 9 through which natural gas flows, and the venturi type atomizer 13 is configured.

  As shown in FIGS. 4 and 5, the basic configuration of the venturi-type atomization apparatus 13 according to the present embodiment is branched from the main flow pipe 9 and the venturi pipe 11 provided in the main flow pipe 9 through which natural gas flows. An LPG supply pipe that includes a branch pipe 15 and a spray nozzle 1 disposed in the venturi pipe 11, the tip of the branch pipe 15 is connected to the outer pipe 2 of the spray nozzle 1, and an LPG is supplied to the liquid supply pipe 4 (Not shown) is connected.

In the venturi type atomization apparatus 13 of the present embodiment, the branch pipe 15 is provided with a flow rate detector 17 for detecting the flow rate of natural gas flowing through the branch pipe 15, and the venturi pipe 11 and the branch pipe 15 in the main flow pipe 9 are provided. A flow rate adjusting valve 19 is provided between the branching portions, and the opening degree of the flow rate adjusting valve 19 is adjusted based on a detection signal of the flow rate detector 17.
Hereinafter, each configuration will be described in detail.

The branch pipe 15 branches from the upstream side of the flow regulating valve 19 in the main flow pipe 9, and the outlet side thereof is connected to the outer pipe 2 of the spray nozzle 1.
The tip of the spray nozzle 1 is disposed upstream of the throat portion 21 of the Benury pipe or the throat portion 21 of the Benury tube.

It is the flow velocity in the inner tube 3 of the spray nozzle 1 that greatly affects the atomization / mixing performance of LPG. This is because when the flow rate of the natural gas supplied to the inner tube 3 becomes a predetermined flow rate, an annular spray flow including LPG in the inner tube 3 is generated, and LPG is atomized and mixed. .
Therefore, the flow passage cross-sectional area of the inner pipe 3 in the spray nozzle 1 is set to such a diameter that the flow rate of the natural gas can maintain the flow rate necessary for generating the annular spray flow even when the city gas is operated at the minimum flow rate. Keep it.
For example, assuming that the fluctuation range of the city gas flow is 300,000 Nm ³ / h to 6,000 Nm ³ / h, when the city gas flow rate is 6,000 Nm ³ / h, which is the lowest flow rate, natural gas is branched. The pipe diameter is set so that the natural gas flow rate of the inner pipe 3 at this time maintains the flow rate necessary for generating the annular spray flow. (At this time, the flow rate of natural gas flowing through the branch pipe 15 is the lowest flow rate assumed as the flow rate of natural gas.)
In addition, if the assumed minimum flow rate is always allowed to flow through the branch pipe 15, LPG atomization and mixing that is easy and stable can be realized. In the following description, the minimum flow rate that gives the flow rate necessary for atomization / mixing of LPG in the branch pipe 15 is defined as a predetermined value A.

The flow rate required for generating the annular spray flow varies depending on the implementation case, but is generally 10 to 20 m / s or more as shown in Tables 1 and 2. Therefore, the inner pipe 3 in the spray nozzle 1 is configured so that the flow rate can be secured by the inner pipe 3 of the spray nozzle 1 and the pressure loss does not become too high at the assumed minimum flow rate of city gas. What is necessary is just to set the diameter and the aspect of the wall member 5.
The diameter of the venturi tube throat portion 21 is designed so that the pressure loss at the maximum design flow rate does not become excessive for the application system.

<Flow detector>
The flow rate detector 17 is provided in the branch pipe 15 and detects the flow rate of natural gas flowing through the branch pipe 15.
It should be noted that a differential pressure detector is provided in place of the flow rate detector 17, and the pressure loss in the branch pipe 15 is detected. You may make it detect the flow volume of the natural gas which flows through.

<Flow control valve>
The flow rate adjustment valve 19 is provided between the venturi pipe 11 and the branch part of the branch pipe 15 in the main flow pipe 9 and adjusts the flow rate of natural gas flowing through the main flow pipe 9 based on the detection signal of the flow rate detector 17. As a result, the flow rate of natural gas flowing through the branch pipe 15 is set to a predetermined flow rate.
In addition, as FIG. 2 shows, the gaseous-phase flow rate for setting it as a cyclic | annular spray flow is influenced by the liquid-phase flow rate. For this reason, a second flow rate detector that detects the amount of LPG supplied to the liquid supply pipe 4 is provided, and a predetermined amount of natural gas flowing through the branch pipe 15 can be calculated and set in consideration of the supplied LPG amount. It is. However, since the control becomes complicated when the second flow rate detector is provided, a constant natural gas flow rate (for example, a flow rate of 20 m / s in the inner pipe 3) is a predetermined amount regardless of the LPG supply amount in practice. Is convenient.

<Description of operation>
Next, the operation of the venturi type fluid atomization apparatus 13 according to the present embodiment configured as described above will be described.
Natural gas supplied from the upstream side also flows into the branch pipe 15 when passing through the branch portion, and flows into the outer pipe 2 of the spray nozzle 1 on the outlet side of the branch pipe 15. Part of the natural gas that flows into the outer pipe 2 flows into the inner pipe 3, entrains the LPG supplied from the liquid supply pipe 4 and generates an annular spray flow in the inner pipe 3, and the atomization and mixing of the LPG is performed. And flows into the throat portion 21 of the Benlury tube.
On the other hand, the natural gas flowing through the main flow pipe 9 also flows into the Bentury pipe throat 21. Therefore, the natural gas to which LPG is added via the branch pipe 15 and the natural gas from the main flow pipe 9 flow into the Benlury pipe throat portion 21 and further pass through the Benury pipe throat portion 21 when the LPG is further passed through. Mixing is promoted.

The flow rate of city gas increases or decreases depending on the demand. For example, when the demand for city gas decreases and the flow rate of the fluid flowing through the flow path decreases, the total flow rate of natural gas flowing through the branch pipe 15 and the main flow pipe 9 decreases. When the flow rate of the natural gas flowing through the branch pipe 15 is reduced below the predetermined value A, the flow velocity of the inner pipe 3 is reduced, the annular spray flow is not formed, and there is a concern that LPG atomization / mixing becomes insufficient.
Therefore, when the flow rate detected by the flow rate detector 17 decreases below the predetermined value A, the flow rate of the natural gas flowing through the branch pipe 15 is maintained at the predetermined value A by decreasing the opening degree of the flow rate adjusting valve 19. .
By maintaining the flow rate of natural gas flowing through the branch pipe 15 at a predetermined value A or higher, the flow rate in the inner pipe 3 is maintained, and the effect of atomization / mixing of LPG can be ensured.

  Conversely, when the demand for city gas increases and the flow rate of the fluid flowing through the flow path increases, the flow rate of natural gas flowing through the branch pipe 15 and the main flow pipe 9 increases.

As the flow rate of natural gas flowing through the branch pipe 15 increases, the pressure loss also increases.
Therefore, when the flow rate detected by the flow rate detector 17 increases from a predetermined value B, the opening degree of the flow rate adjustment valve 19 is increased to increase the amount flowing through the main flow pipe 9, and the flow rate of natural gas flowing through the branch pipe 15 is predetermined. The value B is set. Here, there is a relationship of the predetermined value B ≧ the predetermined value A.
By setting the flow rate of the natural gas flowing through the branch pipe 15 to a predetermined value A or more and B or less, the flow velocity in the branch pipe 15 is maintained within a predetermined range, and LPG can be sufficiently atomized and mixed, and the pressure loss is excessive. Increase can be prevented.

For example, the simplest control method is a case where the predetermined value A = predetermined value B = [natural gas flow rate at the lowest city gas flow rate (natural gas minimum flow rate)].
As in the previous example, assuming that the fluctuation range of the city gas flow rate is 300,000 Nm ³ / h to 6,000 Nm ³ / h, when the city gas flow rate is 6,000 Nm ³ / h, which is the lowest flow rate, The gas is allowed to flow through the branch pipe 15 at a substantially total amount, that is, a flow rate of a predetermined value A (= predetermined value B).
When the city gas flow rate is greater than 6,000 Nm ³ / h, the opening of the flow rate adjustment valve 19 is set so that the flow rate measured by the flow rate detector 17 installed in the branch pipe 15 maintains a predetermined value A. Increasing the natural gas flow rate from the main flow pipe 9 increases. That is, the natural gas flow rate of the predetermined value A always flows through the branch pipe 15 even if the city gas flow rate varies. By doing so, a flow rate necessary for atomization / mixing is always supplied to the branch pipe 15. Further, the velocity component from the main flow tube 9 contributes to the direction of further increasing the flow velocity in the throat portion 21 of the Benlury tube.
In the above description, the predetermined value A is [natural gas flow rate at the minimum city gas flow rate (natural gas minimum flow rate)], but may be simply [minimum city gas flow rate].

  As described above, according to the present embodiment, the natural gas flow rate in the inner pipe 3 can be maintained at a predetermined flow rate even if the flow rate flowing through the flow path changes greatly, and the effect of atomization / mixing of LPG can be achieved. As a result, the pressure loss is not excessively increased.

Here, in order to distribute the natural gas flow rate of the predetermined value A to the branch pipe 15 side, the flow rate adjustment valve 19 is narrowed down so that the pressure loss is equal to or higher than the pressure loss on the branch pipe 15 side including the nozzle. There is a need. Therefore, if the pressure loss of the spray nozzle 1 disposed at the tip of the branch pipe 15 is large, the pressure loss of the entire venturi atomizer 13 becomes large, and the gas pressure for sending out as city gas cannot be maintained.
By using the Venturi type atomizer 13 provided with the spray nozzle 1 of the present invention, atomization can be performed while suppressing pressure loss even in the case of an apparatus having a large rated flow rate, so that the gas supply pressure is not impaired. A reliable heat increase effect can be obtained.

DESCRIPTION OF SYMBOLS 1 Spray nozzle 2 Outer pipe | tube 3 Inner pipe | tube 4 Liquid supply pipe | tube 5 Wall member 7 Tubular member 9 Main flow pipe | tube 11 Venturi pipe | tube 13 Venturi type | mold atomizer 15 Branch pipe | tube 17 Flow rate detector 19 Flow control valve 21 Venturi pipe | tube throat part

Claims (4)

An outer tube that receives a gas supply from the proximal end side and ejects gas toward the distal end side, an inner tube that includes a parallel pipe line disposed coaxially with the outer tube in the outer tube, and an opening of the inner tube A liquid supply pipe that is provided on the inner peripheral surface of the pipe and supplies a liquid to the inner pipe, and a wall member that is provided in the inner pipe and partitions the inside of the inner pipe in the flow direction.
The wall member is provided on the downstream side of the liquid supply part to which the liquid is supplied by the liquid supply pipe in the inner pipe ,
The spray nozzle characterized in that the length in the flow path direction on the downstream side of the connection portion of the liquid supply pipe in the inner pipe is at least five times the flow path diameter of the inner pipe .   The spray nozzle according to claim 1, wherein the wall member is a plate-like member.   The spray nozzle according to claim 1, wherein the wall member is a tubular member. A fluid atomization device using the spray nozzle according to any one of claims 1 to 3, wherein the flow rate detection device detects a flow rate of a gas supplied to the spray nozzle, and a detection value of the flow rate detection device. A fluid atomization apparatus comprising: a flow rate adjusting valve that adjusts a flow rate of the gas flowing through the spray nozzle.

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