JP6748956B2 - Flow stabilizing device in flow path, plant cultivation house including the same, and flow stabilizing method in flow path - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flow stabilizing device and a flow stabilizing method, and more particularly to a flow stabilizing device in a flow channel, a plant cultivation house including the same, and a flow stabilizing method in the flow channel.

Many vegetables and fruits are required to be shipped all year round. Therefore, the producer controls the growing space by heating with heavy oil or cooling with electricity to cultivate vegetables and fruits. However, such a temperature control method has a problem that its running cost is high. Therefore, as a technique relating to a heating and cooling device for a plant cultivation house that cultivates plants by utilizing natural energy such as ground water or solar heat, a groundwater circulation panel is provided on the wall surface surrounding the house as in Patent Document 1 or inside thereof. A house for plant cultivation has been proposed.

In addition, Non-Patent Document 1 reports a study in the case where a vinyl flow path is provided in the flow path of such a panel.

JP-A-2015-128416 "Evaluation of Cooling Performance of Agricultural House Temperature Control System Using Water-Conducting Heat Transfer Panel" The Japan Society of Mechanical Engineers Thermal Engineering Conference 2015"

When a vinyl flow path is provided in the flow path as in Non-Patent Document 1, the vinyl flow path is greatly deformed by the weight of water, and the flow resistance is significantly increased. In addition, there is a possibility that the temperature at the time of water injection may change because some fluid is left without flowing.

As described above, when a member whose flow path is deformed by water injection is used, it is required to reduce flow resistance and stabilize flow.

The flow stabilizing device of the present invention comprises a mixing section having a first input port and a second input port, wherein the mixing section comprises a member that is deformed by a liquid flowing in a flow path. In the passage, the gas injected from the first input port and the liquid injected from the second input port are mixed to form a gas-liquid two-phase flow, and the gas-liquid two-phase flow is flowed from the mixing unit. Let it flow down the street.

A plant cultivation house of the present invention includes the flow stabilizing device and the flow path, and the flow path is provided on at least one of a ceiling and a floor of the plant cultivation house.

Further, in the flow stabilizing method of the present invention, the gas injected from the first input port and the second input port are injected into the flow path constituted by a member that is deformed by the liquid flowing in the flow path. A liquid and a liquid are mixed to form a gas-liquid two-phase flow, and the gas-liquid two-phase flow is caused to flow through the flow path.

This makes it possible to stabilize the flow when a member whose flow path is deformed by water injection is used.

It is a figure which shows the structure of the flow stabilization apparatus of this invention (view seen from the side surface). It is a figure which shows the structure of the flow stabilization apparatus of this invention (the figure seen from the upper part). It is a figure explaining the operation|movement at the time of using the flow stabilization method of this invention for the flow stabilization apparatus of this invention (view seen from the side). It is a figure explaining the operation|movement at the time of using the flow stabilization method of this invention for the flow stabilization apparatus of this invention (view seen from the side). It is a figure (the figure seen from the side) explaining operation|movement when flowing only water into the flow stabilization apparatus of this invention. It is a figure (the figure seen from the side) explaining operation|movement when flowing only water into the flow stabilization apparatus of this invention. It is a figure which shows the temperature control space to which this invention is applied. It is a figure which shows the temperature measurement location in the temperature control space of FIG. It is a figure which shows an example of the experimental temperature control space. It is a figure which shows the temperature change result (preliminary experiment) at the time of cooling of the experimental temperature control space. Transient characteristics of channel inlet/outlet and channel surface temperature without air injection Transient characteristics of the inlet and outlet of the flow path and the surface temperature of the flow path when the air injection amount is 4.76 × 10 ^-5 m ³ /s Transient characteristics of the inlet/outlet of the flow path and the surface temperature of the flow path when the air injection amount is set to 7.62×10 ⁻⁵ m ³ /s Transient characteristics of the inlet/outlet of the flow channel and the surface temperature of the flow channel when the air injection amount is set to 9.50×10 ⁻⁵ m ³ /s Diagram showing τ when the steady state is reached at each measurement position It is a figure which shows an example of the greenhouse for plant cultivation of this invention.

Preferred embodiments of the flow stabilizing device of the present invention will be described below with reference to the drawings.

(Constitution)
FIG. 1 is a diagram showing the configuration of the flow stabilizing device of the present invention (a side view), and FIG. 2 is a diagram showing the configuration of the flow stabilizing device of the present invention (a view seen from the top). As shown in FIG. 1 and FIG. 2, a flow stabilizing device 100 of the present invention includes a mixing section 20 having an air inlet 1 (first input port) and a water inlet 2 (second input port). Prepare The mixing unit 20 includes air (gas) injected from the air injection port 1 and liquid (water) injected from the water injection port (water injection port) 2 into the flow path 4 configured by a member that is deformed by the liquid flowing in the flow path 4. ) And are mixed to form a gas-liquid two-phase flow (mixed-phase flow). Then, the formed gas-liquid two-phase flow is injected into the channel 4 from the channel water injection port 3. Here, the flow path 4 is a flow path that is easily deformable (deformable flow path), such as a tube such as a polyethylene tube or a polyvinyl chloride tube or a hose.

The present device 100 includes a plurality of support rods 5 for supporting the flow path, and FIGS. 1 and 2 show a configuration including n (L1 to Ln) support rods 5. Further, the gas-liquid two-phase flow of air and water flowing in the flow path 4 is drained from the drain port 7 via the flow path drain port 6 of the flow path 4. In this specification, the side of the flow channel water inlet is referred to as upstream and the side of the flow channel outlet is referred to as downstream.

It should be noted that what is injected from the first input port is not limited to air and may be gas (for example, nitrogen gas, carbon dioxide gas, etc.), and what is injected from the second input port is not limited to water and may be liquid. Good (for example, alcohol). You may substitute for arbitrary things as needed.

The air injected into the air inlet 1 may be compressed air created by a compressor 21 as shown in FIG. 1, for example. The air pressure can be adjusted to a desired value by the valve 23 or the like so that the desired air pressure and flow rate can be obtained while the air pressure is measured by the air pressure meter 24 and the flow rate of air is measured by the flow meter 22.

The water injected into the water inlet 2 can be injected into the flow path 4 by sending water with a pump 31, as shown in FIG. 1, for example. While measuring the flow rate of water with the flow meter 32, the flow rate can be adjusted to a desired value with the valve 33 or the like so as to obtain a desired flow rate.

That is, the flow stabilizing device 100 of the present invention creates a gas-liquid two-phase flow from the air (gas) and water (liquid) injected in the mixing section, and sends the gas-liquid two-phase flow to the deformable flow path. You can Therefore, the flow stabilizing device 100 of the present invention is mainly composed of the mixing section 20 having the air inlet 1 and the water inlet 2. The flow stabilizing device 100 is a flow stabilizing device having the flow passage 4 in the main mixing section 20. From a different point of view, the flow stabilizing device 100 can be restated as the flow path 4 including the mixing section 20.

(motion)
Next, the operation of the flow stabilizing device and the flow stabilizing method of the present invention will be described. FIG. 3 is a diagram for explaining the operation when the flow stabilizing method of the present invention is used in the flow stabilizing device of the present invention (a side view), and FIG. 4 is a diagram of the flow stabilizing device of the present invention. It is a figure explaining the operation|movement at the time of using the flow stabilization method of this invention (side view). 3 and 4 show a case where air (gas) 12 and water (liquid) 11 are simultaneously injected to form a gas-liquid two-phase flow and flow into the flow path 4. 5 and 6 show the case where only the water (liquid) 11 is flown into the flow path 4. As shown in FIG. 3, a gas-liquid two-phase flow is caused to flow in the flow path 4 by the air and water. As shown in FIGS. To take.

Compressed air is created by the compressor 21 shown in FIG. 1, and the air pressure and flow rate of the air injected into the flow path 4 are measured by the air pressure gauge 24 and the flow meter 22, respectively, and the valve 23 is adjusted to obtain the desired air pressure and flow rate. To be set. Similarly, the amount of water is adjusted with the valve 33 while measuring with the flow meter 32, and water is injected into the flow path 4 by the pump 31. The air flow (gas) F1 created by the compressor 21 and adjusted by the valve 23 and the water flow (liquid) F2 created by the pump 31 and adjusted by the valve 33 form a gas-liquid two-phase flow (F3) in the mixing section 20. Then, the flow (F3) in the channel water injection port 3 and the flow (F4) in the channel 4 are formed. Eventually, the flow (F5) of the flow path drainage port 6 is discharged. Here, the flow path 4 is a deformable flow path such as a poly tube or a hose, but it becomes a stable flow by introducing air.

Hereinafter, more specific constitutions, methods and effects of the present invention will be described.

(Flow stabilizer)
In the temperature control space described below, the flow stabilizing device 100 of the present invention is configured as follows. First, a poly tube was used for the flow path 4, and a pipe for mixing air and water was manufactured. This pipe corresponds to the mixing section 20. The poly tube flow path was arranged on the support rod 5. By arranging the poly tube flow path on the support rod 5, a panel (referred to as a water-permeable heat transfer panel in this specification) is formed. Here, the support rods 5 were made of stainless steel rods having a diameter of 4 mm, and the arrangement interval was 5 cm. The polytube used this time was made of polyethylene, and had dimensions of 178 cm in length, 25 cm in width and 0.1 mm in thickness when installed. The water-permeable heat transfer panel is a panel in which a flow path of water is provided in the panel and the water exchanges heat with a region (space) in contact with the panel. The present invention is not limited to this water permeable heat transfer panel, and can be applied to a sheet provided with a water flow path (water permeable heat transfer sheet).

An oil-free Vevicon (manufactured by Hitachi Ltd.) was used as the compressor 21 for producing compressed air, and the flow rate of air was measured by a purge meter (manufactured by Tokyo Keiso Co., Ltd.) (flow meter 22). The pressure (air pressure) is measured by a manometer (air pressure gauge 24).

The water (liquid) to be injected is configured to be adjusted to a desired temperature by the equipment of a constant temperature water tank (made by Yamato Scientific Co., Ltd.) and an air-cooled chiller (made by TAITEC), and these equipments are used as a pump 31. The water 11 is injected into the flow path 4.

(Temperature control space)
FIG. 7 is a diagram showing a temperature control space to which the present invention is applied. FIG. 7 is an example in which the flow path of the flow path stabilizing device 100 shown in FIG. 1 according to the present invention is applied to the temperature control space 200, and the structure of the flow stabilizing device 100 is as described above. The ceiling and floor of the temperature control space 200 are the water-permeable heat transfer panels (211 and 212) as described above. Here, a panel (water-permeable heat transfer panel (211, 212)) is formed by the poly tube flow path 4 and the plurality of support bars 5. Although the mixing section 20 is omitted, the mixing section 20 is connected to the polytube flow path 4 provided in the panels (211 and 212). The four side walls (201 to 204) were heat insulating walls (heat insulating boards). Note that, in FIG. 7, the heat insulating wall 204 is omitted because a part of the heat insulating wall is illustrated. The thickness of the styrofoam used as the heat insulating material of the heat insulating wall is 5 cm. This temperature control space had a width of 0.9 m, a depth of 1.8 m, and a height of 1.8 m. FIG. 9 shows the temperature control space 200 in which the actual measurement is performed. 201 and 202 are the above-mentioned heat insulating walls (heat insulating boards), and 211 is a water-permeable heat transfer panel. The configurations of the panels (211 and 212) are not limited to the above, and various configurations may be adopted. For example, the support rod 5 may have a mesh shape as shown in FIG.

For the performance evaluation of the present invention, the experimental temperature control space 200 was installed in the laboratory. Since the following experimental results are in the laboratory, there is no heating in the experimental temperature control space by sunlight irradiation.

For temperature measurement, thermocouples were installed in a plurality of experimental temperature control spaces 200 as shown in FIG. Note that in FIG. 8, the side walls 202 to 204 are omitted because the temperature measurement points inside and outside the temperature control space 200 of FIG. 7 are illustrated. Further, reference numeral 250 in FIG. 9 is (the cable of) the thermocouple for temperature measurement.

(Cooling characteristics of experimental temperature control space)
First, as a preliminary experiment, a cooling experiment of the experimental temperature control space 200 was performed. The measurement was started from the condition in which the laboratory (OT) temperature was kept at 32° C. by using the cooling water adjusted to 15° C. by using the above constant temperature water tank and the air-cooled chiller. The flow rate at this time was 300 mL/min.

Further, there are a total of 6 temperature measurement points, one in the laboratory (that is, outside the temperature control space 200), one in the center of the temperature control space, and one inflow/outflow port for each of the upper and lower panels. The positions of these thermocouples are OT outside the temperature control space, IN at the center of the temperature control space, UI at the upper panel inlet, UO at the upper panel, and LI at the lower panel inlet. The outlet on the bottom panel is the location shown in FIG. 8 as LO.

FIG. 10 shows the temperature change result (preliminary experiment result) during cooling of the experimental temperature control space. It can be seen that the water temperature at the panel inlet is about 18°C, not 15°C. This is because the high temperature water in the poly tube (flow channel 4) at the start of the experiment is likely to stay in the poly tube due to the deformation of the flow channel.

(Verification experiment of effect of invention)
Next, in order to verify the effect of the present invention, an experiment was conducted with and without air injection. As experimental conditions, the water in the laboratory (OT) and the water inside the polytube were adjusted to 12° C., and heated water at 45° C. was passed at 100 mL/min.

The temperature response of the polytube surface was evaluated for the following four cases including the case without air injection (flow rate 0). The scale indicates the scale of the purge meter.

(1) 0 m ³ /s (scale ---): No air injection (2) 4.76×10 ^-5 m ³ /s (scale 0.5)
(3) 7.62×10 ⁻⁵ m ³ /s (scale 0.8)
(4) 9.50×10 ⁻⁵ m ³ /s (scale 1.0)

In addition, the position of the flow channel water inlet 3 (the position of UI) of the heat transfer panel 211, the position of the flow channel drain port 6 (the position of UO), and the end of the poly tube (flow channel) 4 on the side of the flow channel water inlet 3 The surface temperature of the polytube (flow path) 4 at a point (Px:x is a distance (cm)) separated by a distance x from the position as a starting point was measured. Specifically, the points of x=0 cm, 44.5 cm, 89 cm, 133.5 cm, and 178 cm and the points of UI and UO were measured. 11 to 14, points at x=0 cm, 44.5 cm, 89 cm, 133.5 cm, and 178 cm are shown as P ₀ , P _44.5 , P ₈₉ , P _133.5 , and P ₁₇₈ , respectively.

With respect to the above four cases ((1) to (4)), the inlet/outlet (UI, UO) of the channel and the points P ₀ , P _44.5 , P ₈₉ , P _133.5 , and P ₁₇₈ of the channel are provided. 11 to 14 show the results of measurement of the transient characteristics of the surface temperature while changing the air flow rate. FIG. 11 shows transient characteristics of the flow path inlet/outlet and the flow path surface temperature when there is no air injection (when the air injection amount is 0 m ³ /s). FIG. 12 shows the transient characteristics of the inlet and outlet of the channel and the surface temperature of the channel when the air injection amount is set to 4.76×10 ⁻⁵ m ³ /s. FIG. 13 shows the transient characteristics of the inlet and outlet of the channel and the surface temperature of the channel when the air injection amount is set to 7.62×10 ⁻⁵ m ³ /s. FIG. 14 shows the transient characteristics of the inlet and outlet of the channel and the surface temperature of the channel when the air injection amount is 9.5×10 ⁻⁵ m ³ /s.

In the measurement results of FIGS. 11 to 14, the temperature measurement values at the respective observation points (UI, UO, P ₀ , P _44.5 , P ₈₉ , P _133.5 , P ₁₇₈ ) and the measurement time thereof are as follows. The equation is plotted as a dimensionless quantity.

Dimensionless temperature formula (Formula 1 below)

Dimensionless time formula (Formula 2 below)

Here, T is the temperature, T _C is the initial temperature, T _H is water passing temperature, [rho is the density of water, Q is passing amount of water per unit time, t is the elapsed time, m is not previously stayed in the channel It is the mass of water. That is, the dimensionless temperature Θ shows the ratio of how close to the water flow temperature, and the dimensionless time τ shows how many times all the water is exchanged assuming that the water does not mix.

Taking the inlet water temperature as an example when no air is injected (FIG. 11), the dimensionless temperature rises with the start of water flow, and when the dimensionless time τ reaches 0.26, it takes a constant value. This constant time is defined as a steady state, and the dimensionless temperature in this steady state is Θmax.

The measurement time without air injection (case (1)) was about 3 hours, and the measurement time with air injection (cases (2) to (4)) was 1 hour each. Therefore, in the data of each case with air injection, the maximum Θ in the number of measured data 3600 was set to Θmax. This is because the measured temperature gradually approaches the steady-state value and it is difficult to specify the time.

(Location-dependent non-dimensional temperature (Θ))
As the measurement point on the downstream side (the measurement point closer to the outlet UO of the upper panel) decreases, the rate of temperature increase decreases, and the constant temperature (dimensionless temperature in the steady state) also decreases. The exit temperature (temperature at UO) is only up to a dimensionless temperature Θ of about 0.5.

When air is injected (for example, the case of (4)), the temperature rises in a short time (the temperature responsiveness is improved), and the temperature in the steady state rises, albeit slightly.

(Dimensionless temperature in steady state (Θ))
In order to show the temperature in the steady state, Table 1 shows the dimensionless temperature in the steady state at each position in the presence or absence of air injection (cases (1) to (4)). The temperature is slightly lower in the vicinity of the center of the flow path when air is injected, but the temperature becomes higher toward the downstream side. The temperature drop near the center of the flow path is due to the fact that the pulsating flow is generated at the inlet and the outflow is blocked because the air injection amount is too small, and it can be improved by increasing the air injection amount. Guessed. Since the downstream temperature is rising, it is considered that the flow condition has been improved.

Table 1: Steady-state non-dimensional temperature at each position with and without air injection

(Temperature response)
In order to confirm the temperature responsiveness, the time required to reach a steady state is shown in FIG. 15 and Table 2. Here, the time to reach a steady state depending on the presence or absence of air injection is compared for each point. The time to reach the steady state is long in the vicinity of the inlet of the flow path because the above-mentioned air injection amount is too small. The time to reach the steady state becomes shorter toward the downstream side, and the steady time is about 0.48 (when most accelerated (x=44.5 cm)) to 0.78 (when most accelerated (exit)) times. Come to a state.

Table 2: Dimensionless time to reach steady state at each position with and without air injection

When air is injected, water comes out as a pulsating flow together with the air. Due to the influence of this, at the inlet and x=0 cm (P ₀ ), the steady state is reached at an early stage without air injection. However, it can be seen that the steady state is reached at a much earlier stage with air injection along the downstream side. The experimental results showed that the smaller the air flow rate, the smaller the air flow rate and the better the responsiveness.

From the above, it can be said that the present invention is effective from the transient characteristics of the flow state and temperature.

In the above-mentioned embodiment, the flow paths 4 are placed on the metal rods arranged in parallel, but instead of this, the metal rods may be placed on a mesh-shaped shelf.

Moreover, in the above-mentioned Example 1, when external light (sunlight etc.) is taken in inside the temperature control space, especially in the case of application to a greenhouse for plant cultivation described later, the water-permeable heat transfer panel (211 and 212) is used. The member forming the flow path 4 may be replaced with a permeable material. In this case, the side panel may be transparent as well. However, since the flow stabilizing device of the present invention generates a gas-liquid two-phase flow and causes the fluid to flow through the flow channel, it exerts its effect when the flow channel uses a member that is deformed by water injection. To do. Deformation of the flow channel is also seen in drain tubes that flow rainwater. In particular, in the case of outdoor rainwater drainage, since it can be controlled to stop rainwater, hygiene problems such as bow hula can be solved.

As described above, the present invention can reduce the flow resistance of the flow path when using a member such as a poly tube or a hose, or a flow path made of vinyl that is deformed by water injection. An air inlet is provided at the inlet of the flow passage, and air is also sent in along with the liquid injection, and the amount of deformation of the flow passage made of a member that is deformed by water injection is reduced, so that the flow in the flow passage is facilitated. This facilitates the outflow of liquid that was previously staying in the flow path made of a member that is deformed by water injection, so the temperature response of the flow path surface made of a member that is deformed by water injection Can be expected to improve.

(House for plant cultivation)
FIG. 16 shows an example of the greenhouse for plant cultivation of the present invention. This is a structural example of a greenhouse for plant cultivation using the flow stabilizing device of the present invention. The greenhouse for plant cultivation in the present embodiment includes the temperature control space 200 and the vinyl ceiling 301 shown in the first embodiment as main components of the house 300. The temperature control space 200 is provided with water permeable heat transfer panels (211 and 212), and the water permeable heat transfer panels have air and water as a gas-liquid two-phase flow from the flow stabilizer of the present invention. The heat transfer panels (211 and 212) are filled with water.

According to the flow stabilizing method of the present invention, the gas injected from the first input port and the second input port are injected into the flow path formed of a member that is deformed by the liquid flowing in the flow path. A liquid and a liquid are mixed to form a gas-liquid two-phase flow, and the gas-liquid two-phase flow is caused to flow through the flow path.

In the present invention, the flow path 4 is a deformable flow path such as a poly tube or a hose. INDUSTRIAL APPLICABILITY The present invention can be applied to a flow path provided with a member such as a polytube or a hose that is deformable so that it can be folded when nothing flows in it, as in the above-described example.

INDUSTRIAL APPLICABILITY As described above, the present invention can be applied to a flow path in which the flow path 4 has a folded diameter (a widthwise dimension in a folded state) larger than the diameter of the flow path water inlet 3 or the flow path drain port 6. The invention is not limited to this, and can be applied to a flow path in which the bent diameter of the flow path 4 is the same as the diameter of the flow path water injection port 3 or the flow path drainage port 6. The shape of the flow path 4 viewed from the upper surface (top view) is not limited to the rectangular shape, and may be applied to flow paths having various shapes such as an ellipse and a fan shape according to the shape of the panel.

INDUSTRIAL APPLICABILITY The present invention can be generally used in devices and equipment related to a mechanism for stabilizing the flow of a flow path, which is composed of a member that is deformed by the liquid flowing in the flow path. In particular, a panel/sheet is provided in which a flow path for water is provided in a panel or sheet that is placed on the ceiling or floor of a greenhouse for plant cultivation, and the water exchanges heat with the area (space) in contact with the panel or sheet. It can be used as a house for plant cultivation.

1 Air injection port 2 Water injection port 3 Flow path injection port 4 Flow path 5 Support rod 6 Flow path drain port 7 Drain port 20 Mixing section 21 Compressor 24 Air pressure gauge 22, 32 Flow meter 23, 33 Valve 31 Pump 100 Flow stabilization Device 200 Temperature control space 201-204 Thermal insulation wall (insulation board)
211, 212 Water-permeable heat transfer panel 250 Thermocouple 300 House 301 Vinyl ceiling

Claims (7)

A flow path provided with a member that is deformed by the liquid flowing in the flow path,
A mixing unit having a first input port and a second input port,
The mixing unit mixes a gas injected from the first input port with a liquid injected from the second input port to form a gas-liquid two-phase flow,
A flow stabilizing device for flowing the gas-liquid two-phase flow from the mixing section to the flow path. The flow stabilizing device according to claim 1, wherein the member is transparent. The flow stabilizing device according to claim 1, wherein the member is a tube or a hose. The flow stabilizing device according to any one of claims 1 to 3, wherein the member is polyethylene or polyvinyl chloride. The flow stabilizing device according to any one of claims 1 to 4, wherein the gas is air and the liquid is water. A flow stabilizing device according to any one of claims 1 to 5,
A plant cultivation house, wherein the flow path is provided in at least one of a ceiling and a floor of the plant cultivation house. A flow stabilizing method using the flow stabilizing device according to claim 1.
The gas and the liquid are mixed to form a gas-liquid two-phase flow, and the gas-liquid two-phase flow is caused to flow in the flow path, thereby stabilizing the flow of the liquid in the flow path. And a flow stabilization method.