JP3607364B2 - Flow measuring device - Google Patents

Description

【００１１】
により、噴射混相流中の液体の流出体積速度Ｑ_{Ｌ，ｏｕｔ} （ｔ）が推定される。ただし、ここでは、液体１１は、非圧縮性流体であるとしている。
すなわち（２）式によると、混合室１０に流入する液体１１の流入体積速度Ｑ_Ｌ，ｉｎ（ｔ）と、混合室１０内の気体１２の体積Ｖ_Ｇ （ｔ）もしくはその体積変化｛ｄＶ_Ｇ （ｔ）／ｄｔ｝とを測定することにより、噴射混相流中の流体の流出体積速度Ｑ_{Ｌ，ｏｕｔ} （ｔ）を求めることができる。
【００１２】
（液体の流入体積速度Ｑ_Ｌ，ｉｎ（ｔ）の測定）
これは、液体のみが液体流入管１３内を流れている状態における液体の流入体積速度であるから、例えばレーザドプラ流速計、超音波流速計等によりその液体１１の流速Ｖ_Ｌ，ｉｎ（ｔ）を測定し、管１３（図１参照）の内断面積をＳ、補正係数をαとして、
Ｑ_Ｌ，ｉｎ（ｔ）＝α・Ｓ・Ｖ_Ｌ，ｉｎ（ｔ） ……（３）
により求めることができる。この、液体流入管１３内を流れる液体の体積速度を求める手法自体は従来知られており、また流速計についても種々の原理に基づくものが従来知られており、ここでは、これ以上の詳細説明は省略する。
【００１３】
（混合室内の気体の体積ないし体積変化の測定）
本発明は、混合室内の体積ないし体積変化を求める手法自体を特定の手法に限定するものではなく、例えば混合室１０を透明体で形成し混合室１０の内部の様子を連続的に撮影して画像処理を行なうこと等によってその体積ないし体積変化を測定するものであってもよいが、ここでは、例えば上述したガソリンの噴入のような、例えば数ｍｓｅｃを単位とした高速の流量変化を知ることのできる手法として、以下の原理に基づく、気体の体積を測定する手法を説明する。
【００１４】
混合室１０内に、角周波数ω，体積速度Ｑ_Ｏ の音波Ｑ_Ｏ ｅｘｐ（ｊωｔ）を発生する音源を配置して混合室１０内の気体に音波（圧力変化）を与え、その混合室１０内の気体の圧力Ｐ_Ｏ と、角周波数ωの音圧Ｐ_Ｗ ｅｘｐ（ｊωｔ）を測定する。尚、ｊは虚数単位を表わす。ここでは、混合室１０内の代表的な長さが音波Ｑ_Ｏ ｅｘｐ（ｊωｔ）の波長に比べ十分小さいものとする。
【００１５】
混合室１０内部の気体１２の密度をρ、粒子速度（ベクトル）をｖとしたとき、質量に関する連続の式は、
【００１６】
【数２】

【００１７】
で表わされる。また、混合室１０内の気体１２の圧力をＰとし、
Ｐ ＝ Ｐ_Ｏ ＋ ｐ
ρ ＝ ρ_Ｏ ＋ ρ´
ｖ ＝ ｖ_Ｏ ＋ ｖ´＝ ｖ´ ……（５）
のように、平行状態での圧力Ｐ_Ｏ ，密度ρ_Ｏ ，速度ｖ_Ｏ と、それからの偏差ｐ（音圧），ρ´，ｖ´との和で表わす。ただし、粒子速度ｖについては、平衡状態では気体の流れはないものとし、したがって粒子速度ｖ_Ｏ はｖ_Ｏ ＝０とする。
【００１８】
（５）式を（４）式に代入すると、Ｐ_Ｏ ，ρ_Ｏ は一定値であるため、
【００１９】
【数３】

【００２０】
となる。この（６）式の左辺の第３項ｖ´・ｇｒａｄ（ρ´）は２次の微小量であるためこれを省略すると、
【００２１】
【数４】

【００２２】
が成立する。
更に、熱力学考察より、気体の密度ρを圧力ＰとエントロピーＳとの関数
ρ ＝ ρ（Ｐ，Ｓ） ……（７）
と考えるとともに、熱伝導や粘性の影響は無視できる等エントロピー過程を考え、
【００２３】
【数５】

【００２４】
ここで（…）_Ｓ，Ｏ の‘ｏ’は平衡状態での値であることを示している。（７）式は、
【００２５】
【数６】

【００２６】
となる。
次に、上記（９）式を混合室１０の気体１２の部分全体（Ｖ_Ｇ ）にわたって積分する。
ここで、上述したように、混合室１０の長さディメンションは音波の波長に比べて十分小さい場合は、音圧は混合室１０内部で一様と考えてよく、
【００２７】
【数７】

【００２８】
但し、ｘはベクトルを表わす
となる。
さて、（９）式をＶ_Ｇ 内で積分し、
【００２９】
【数８】

【００３０】
を得る。ただし、簡単のため音源は平面ピストン音源とし、音源の振動速度の法線成分をＶ_ｎ ・ｅｘｐ（ｊωｔ），音源の面積をＡ、また、
Ｐ ＝ Ｐ_Ｗ ｅｘｐ（ｊωｔ）
とし、共通因子ｅｘｐ（ｊωｔ）は省略した。（１１）式より、
【００３１】
【数９】

【００３２】
Ｑ_Ｏ ＝ −Ａ・Ｖ_ｎ ……（１３）
を得る。理想気体の場合には、
【００３３】
【数１０】

【００３４】
が成り立ち、（１２）式は、
【００３５】
【数１１】

【００３６】
となる。従って
【００３７】
【数１２】

【００３８】
を得る。
尚、今まで、Ｖ_Ｇ ，Ｐ_Ｏ は一定としたが、これらがｅｘｐ（ｊωｔ）に比べ、ゆっくり変化する場合には、
Ｖ_Ｇ → Ｖ_Ｇ （ｔ）， Ｐ_Ｏ → Ｐ_Ｏ （ｔ） ……（１８）
としてよい。また、（５）式以降ｖ_Ｏ ＝０としたが、気体の熱伝導の影響は無視し得るとして（１０）式で仮定したのと同じ理由で、密度ρ＝ρ_０ ＋ρ’も混合室内では空間的に一様に変化すると考えるならば、そして、音波の時間変動が背景のＰ_０ （ｔ）等の時間変動に比べ十分速いとするならばｖ_Ｏ ≠０の場合にも、（７）式は成り立つことになる。
【００３９】
ここで、上記（１７）式において、音源の体積速度Ｑ_Ｏ は測定、制御可能な量であり、圧力Ｐ_Ｏ ，音圧Ｐ_Ｗ も測定可能量である。
ところで（１７）式中に示される比熱比γは、理想気体の場合は比熱比でよかったが、現実には、混合室１０の内壁と気体との間の熱伝導は無視できない。そこで、上記（１７）式を、
【００４０】
【数１３】

【００４１】
と書き換える。ここで、γ_ｅｆｆ は低周波でγ_ｅｆｆ ≒１、高周波では、γ_ｅｆｆ ≒γとなる複素数値をとる無次元量である。このγ_ｅｆｆ は球や円筒内部等の簡単な境界条件の場合は容易に算出し得るが、図１に示すような複雑な系については解析的な手法では一般的には求めることはできない。
そこで、混合室１０の内部の形状、攪拌状態等とγ_ｅｆｆ との関係マップを、測定データを基に作成しておき、その関係マップから求められたγ_ｅｆｆ を用いてＶ_Ｇ を推定することが望ましい。
【００４２】
このようにして、（３）式に基づいて液体の流入体積速度Ｑ_Ｌ，ｉｎ（ｔ）を求めるとともに、（１７）式ないし（１９）式に基づいて混合室内部の気体の体積Ｖ_Ｇ を求めることにより、（２）式から、噴射混相流中の液体の流出体積速度Ｑ_{Ｌ，ｏｕｔ} （ｔ）が求められる。
尚、上記説明では、混合室１０内部の体積Ｖ_Ｏ としては、混合室１０内部の幾何学的形状のみにより定まる体積を想定したが、必要に応じて、幾何学的な体積に代わり、実効的な体積を想定してもよい。また必要に応じて、混合室１０に流入する気体１２の流路に音響フィルタを取り付けてもよい。
【００４３】
【実施例】
以下、本発明の実施例について説明する。
図２は、図１に示す混合室に、本発明の流量測定装置の一実施例を取り付けた状態を示す模式図である。この図２中に記入された符号は、図１もしくは図３に記入された符号、もしくは、前述した各式中に表われた符号と同一の意味を有しており、ここでは重複説明は省略する。
【００４４】
液体流入管１３には、その管１３の内部を流れる液体１１の流速を測定する、レーザドプラ流速計（ＬＤＶ）２０が備えられており、流速Ｖ_Ｌ，ｉｎ（ｔ）が求められ、演算部２６では、前述した（３）式に従って、入力された流速Ｖ_Ｌ，ｉｎ（ｔ）を基に、液体１１の流入体積速度Ｑ_Ｌ，ｉｎ（ｔ）が求められる。尚、本実施例ではＬＶＤ２０と、演算部２６の流速Ｖ_Ｌ，ｉｎ（ｔ）を流入体積速度Ｑ_Ｌ，ｉｎ（ｔ）に換算する機能とを合わせた構成が、本発明にいう流量センサに対応する。
【００４５】
また、混合室１０の壁には、音源２１，圧力センサ２２，音圧センサ２３が備えられている。圧力センサ２２は、混合室１０の内部の気体１２の静圧（もしくはｅｘｐ（ｊωｔ）と比べゆっくりと変化する準静圧）を測定するものであり、音圧センサ２３は、角周波数ωの圧力変化を測定するものである。ここでは、名称で区別しているが、圧力センサ２２および音圧センサ２３は各用途を満足するものであればよく、各用途を満足する限り、同一仕様のものであってもよい。また、その場合、気体の圧力ないし音圧を直接測定する部分は１つであって、フィルタ等により圧力（静圧ないし準静圧）と音圧（角周波数ω）とに分けてもよい。
【００４６】
音源２１は、その音源に入力される駆動信号Ｄに応じて混合室１０の内部側の面（面積Ａ）がＱ_Ｏ ｅｘｐ（ｊωｔ）で振動する。その駆動信号Ｄは、振幅Ｑ_Ｏ の情報を担持する信号として、演算部２６に入力される。
圧力センサ２２は、混合室１０内部の気体１２の圧力を測定するためのセンサであり、圧力センサ２２からの出力信号は、ローパスフィルタ２４に入力され、静圧ないし準静圧Ｐ_Ｏ を表わす信号が抽出されて演算部２６に入力される。
【００４７】
また、音圧センサ２３は、混合室１０の内部の気体１２の、角周波数ωの音圧Ｐ_Ｗ を測定するためのセンサであり、音圧センサ２３からの出力信号は、バンドパスフィルタ２５に入力され、角周波数ωの音圧Ｐ_Ｗ を表わす信号が抽出されて演算部２６に入力される。
演算部２６には、この図２に示す系においてあらかじめ測定されたγ_ｅｆｆ についてのデータが格納されており、演算部２６では、前述した（１９）式に基づいて、混合室１０の内部の気体に体積Ｖ_Ｇ （ｔ）が求められる。
【００４８】
このようにして、演算部２６では、液体１１の流入体積速度Ｑ_Ｌ，ｉｎ（ｔ）と、混合室１０の内部の気体１２の体積Ｖ_Ｇ （ｔ）が求められ、さらに、前述した（２）式に基づいて液体１１の流出体積速度Ｑ_{Ｌ，ｏｕｔ} （ｔ）が求められる。
【００４９】
【発明の効果】
以上説明したように、本発明によれば、噴射混相流中の液体の噴射量を、気体の噴射量とは分離して測定することができる。
【図面の簡単な説明】
【図１】本発明の原理説明図であり、図３に示す混合室の模式図に、各種記号を書き加えた図である。
【図２】図１に示す混合室に、本発明の流量測定装置の一実施例を取り付けた状態を示す模式図である。
【図３】混合室の模式図である。
【符号の説明】
１０ 混合室
１１ 液体
１２ 気体
１３ 液体流入管
２０ レーザドプラ流速計
２１ 音源
２２ 圧力センサ
２３ 音圧センサ
２４，２５ フィルタ
２６ 演算部[0001]
[Industrial application fields]
The present invention relates to a flow rate measuring device for measuring a flow rate of a liquid in a multiphase flow ejected from a mixing chamber for mixing a gas and a liquid.
[0002]
[Prior art]
Conventionally, a technique for mixing and injecting a gas and a liquid in a mixing chamber as described above has been used in, for example, an apparatus for injecting gasoline into an engine of an automobile.
FIG. 3 is a schematic view of the mixing chamber.
A liquid (for example, gasoline) 11 and a gas (for example, air) 12 flow into the mixing chamber 10, and they are mixed inside the mixing chamber 10 and injected from the mixing chamber 10.
[0003]
[Problems to be solved by the invention]
For example, it is desired to measure the temporal change in the amount of gasoline injected into the engine as described above, but no appropriate measurement method has been found so far.
For example, it is conceivable to employ a so-called momentum method in which a mixed phase flow ejected from the mixing chamber 10 is sprayed on a pressure sensor or the like to obtain an injection amount from the pressure change. It is impossible to separate the spray pressure from the spray pressure, and therefore it is not possible to measure the ejection amount of only the liquid in the multiphase flow.
[0004]
In view of the above circumstances, an object of the present invention is to provide a flow rate measuring device that measures a liquid injection amount in an injection multiphase flow separately from a gas injection amount.
[0005]
[Means for Solving the Problems]
The flow rate measuring device of the present invention that achieves the above object is characterized in that the amount of liquid ejected in a mixed phase flow in which both the gas and the liquid are ejected is injected from a predetermined mixing chamber into which both the gas and the liquid flow. A flow measuring device for measuring,
(1) A flow sensor for measuring the flow rate of the liquid flowing into the mixing chamber (2) A volume sensor for measuring the volume or volume change of the gas in the mixing chamber (3) The flow rate measured by the flow sensor and the volume sensor A calculation unit is provided that calculates the amount of liquid ejected in the multiphase flow based on the volume or volume change.
[0006]
Here, in the flow rate measuring device of the present invention, the volume sensor of the above (2) is
(2-1) A sound source that emits sound waves including at least a predetermined frequency in the gas in the mixing chamber (2-2) A pressure sensor that measures the pressure in the mixing chamber (2-3) A predetermined frequency in the mixing chamber It is preferable that a sound pressure sensor for measuring the sound pressure is provided.
[0007]
[Action]
FIG. 1 is a diagram for explaining the principle of the present invention, in which various symbols are added to the schematic diagram of the mixing chamber shown in FIG. The flow rate measuring device of the present invention is not applied only to the rectangular mixing chamber or the like as shown in FIG. 1, but for the sake of easy understanding, hereinafter, the measurement of the present invention will be described with reference to FIG. The principle will be described.
[0008]
In the system shown in FIG. 1, the inflow volume velocity of the liquid 11 into the mixing chamber 10 is Q _{L, in} (t), the inner volume of the mixing chamber 10 is V _O , and the volume of the liquid 11 in the mixing chamber 10 is V _L ( t), let V _G (t) be the volume of gas in the mixing chamber 10, and let Q _{L, out} (t) be the outflow volume velocity of the liquid in the multiphase flow injected from the mixing chamber 10. Note that (t) represents a function of time t. What is being obtained here is the liquid outflow volume velocity Q _{L, out} (t).
[0009]
The volume V _L (t) of the liquid 11 in the mixing chamber 10 is
V _L (t) = V _O −V _G (t) (1)
Is given by
[0010]
[Expression 1]

[0011]
Thus, the outflow volume velocity Q _{L, out} (t) of the liquid in the jet mixed phase flow is estimated. However, here, the liquid 11 is assumed to be an incompressible fluid.
That is, according to the equation (2), the inflow volume velocity Q _{L, in} (t) of the liquid 11 flowing into the mixing chamber 10 and the volume V _G (t) of the gas 12 in the mixing chamber 10 or its volume change {dV _G By measuring (t) / dt}, the outflow volume velocity Q _{L, out} (t) of the fluid in the jet multiphase flow can be obtained.
[0012]
(Measurement of liquid inflow volume velocity Q _{L, in} (t))
This is the inflow volume velocity of the liquid in a state where only the liquid is flowing in the liquid inflow tube 13, and the flow velocity V _{L, in} (t) of the liquid 11 is determined by, for example, a laser Doppler velocimeter or an ultrasonic velocimeter. Measured, S is the inner cross-sectional area of the tube 13 (see FIG. 1),
Q _{L, in} (t) = α · S · V _{L, in} (t) (3)
It can ask for. The technique itself for determining the volume velocity of the liquid flowing in the liquid inflow pipe 13 is conventionally known, and the anemometer is also known based on various principles. Here, further detailed explanation is given here. Is omitted.
[0013]
(Measurement of volume or volume change of gas in mixing chamber)
The present invention does not limit the method itself for obtaining the volume or volume change in the mixing chamber to a specific method. For example, the mixing chamber 10 is formed of a transparent body and the inside of the mixing chamber 10 is continuously photographed. The volume or volume change may be measured by performing image processing or the like, but here, for example, a high-speed flow rate change in units of several milliseconds, such as the above-described gasoline injection, is known. As a technique that can be used, a technique for measuring the volume of gas based on the following principle will be described.
[0014]
A sound source that generates a sound wave Q _O exp (jωt) having an angular frequency ω and a volume velocity Q _O is disposed in the mixing chamber 10 to apply a sound wave (change in pressure) to the gas in the mixing chamber 10. the pressure _{P O} of the gas, measuring the sound pressure of the angular frequency ω _P W exp (jωt). J represents an imaginary unit. Here, it is assumed that the representative length in the mixing chamber 10 is sufficiently smaller than the wavelength of the sound wave Q _O exp (jωt).
[0015]
When the density of the gas 12 inside the mixing chamber 10 is ρ and the particle velocity (vector) is v, the continuous equation for mass is:
[0016]
[Expression 2]

[0017]
It is represented by Further, the pressure of the gas 12 in the mixing chamber 10 is P,
P = _PO + p
ρ = ρ _O + ρ ′
_{v = v O + v'= v'} ...... (5)
The pressure P _O , the density ρ _O , the velocity v _O in the parallel state and the deviation p (sound pressure), ρ ′, v ′ therefrom are expressed as follows. However, regarding the particle velocity v, it is assumed that there is no gas flow in the equilibrium state, and therefore the particle velocity v _O is set to v _O = 0.
[0018]
By substituting equation (5) into equation (4), P _O and ρ _O are constant values.
[0019]
[Equation 3]

[0020]
It becomes. Since the third term v ′ · grad (ρ ′) on the left side of the equation (6) is a secondary minute amount, if omitted,
[0021]
[Expression 4]

[0022]
Is established.
Furthermore, from the thermodynamic consideration, the density ρ of the gas is a function ρ = ρ (P, S) of the pressure P and the entropy S (7)
And an isentropic process where the effects of heat conduction and viscosity are negligible,
[0023]
[Equation 5]

[0024]
Here, (...) “o” of _{S and O} indicates a value in an equilibrium state. Equation (7) is
[0025]
[Formula 6]

[0026]
It becomes.
Next, the above equation (9) is integrated over the entire portion (V _G ) of the gas 12 in the mixing chamber 10.
Here, as described above, when the length dimension of the mixing chamber 10 is sufficiently small compared to the wavelength of the sound wave, the sound pressure may be considered to be uniform inside the mixing chamber 10,
[0027]
[Expression 7]

[0028]
However, x represents a vector.
Now, integrated in the _{V G} the equation (9),
[0029]
[Equation 8]

[0030]
Get. However, for simplicity, the sound source is a flat piston sound source, the normal component of the vibration speed of the sound source is V _n · exp (jωt), the area of the sound source is A,
P = P _W exp (jωt)
And the common factor exp (jωt) was omitted. From equation (11)
[0031]
[Equation 9]

[0032]
Q _O = −A · V _n (13)
Get. In the case of an ideal gas,
[0033]
[Expression 10]

[0034]
And the equation (12) is
[0035]
[Expression 11]

[0036]
It becomes. Therefore, [0037]
[Expression 12]

[0038]
Get.
Until now, V _G and _PO have been constant, but when these change slowly compared to exp (jωt),
_{V G → V G (t)} , P O → P O (t) ...... (18)
As good as Also, (5) was the expression since v _{O =} 0, for the same reason that the influence of the heat conduction gas was assumed as negligible in (10), the density ρ = ρ _{0 +} ρ 'in the mixing chamber If considered spatially uniform changes, and, even if the time variation of the sound wave is v _O ≠ 0 if a sufficiently fast compared to the time variation of P such _{0 (t)} of the background, (7) The formula will hold.
[0039]
Here, in the above equation (17), the volume velocity Q _O of the sound source is a quantity that can be measured and controlled, and the pressure P _O and the sound pressure P _W are also measurable quantities.
Incidentally, the specific heat ratio γ shown in the equation (17) may be the specific heat ratio in the case of an ideal gas, but in reality, the heat conduction between the inner wall of the mixing chamber 10 and the gas cannot be ignored. Therefore, the above equation (17) is changed to
[0040]
[Formula 13]

[0041]
And rewrite. Here, gamma _eff is gamma _eff ≒ 1 at low frequencies, the high frequency is a dimensionless quantity that takes complex values to be γ _eff ≒ γ. This γ _eff can be easily calculated in the case of a simple boundary condition such as the inside of a sphere or cylinder, but it cannot be generally obtained by an analytical method for a complicated system as shown in FIG.
Therefore, the internal shape of the mixing chamber 10, a relation map of the stirring conditions, etc. and gamma _eff, advance to create a measurement data group, to estimate the V _G using a gamma _eff obtained from the relation map Is desirable.
[0042]
In this way, the liquid inflow volume velocity Q _{L, in} (t) is obtained based on the equation (3), and the gas volume V _G in the mixing chamber is calculated based on the equations (17) to (19). By obtaining, the outflow volume velocity Q _{L, out} (t) of the liquid in the jet mixed phase flow is obtained from the equation (2).
In the above description, the volume V _O inside the mixing chamber 10 is assumed to be a volume determined only by the geometric shape inside the mixing chamber 10. However, if necessary, an effective volume can be used instead of the geometric volume. A large volume may be assumed. Moreover, you may attach an acoustic filter to the flow path of the gas 12 which flows into the mixing chamber 10 as needed.
[0043]
【Example】
Examples of the present invention will be described below.
FIG. 2 is a schematic view showing a state in which one embodiment of the flow measuring device of the present invention is attached to the mixing chamber shown in FIG. 2 has the same meaning as the code entered in FIG. 1 or FIG. 3 or the code shown in each of the above-mentioned formulas, and redundant description is omitted here. To do.
[0044]
The liquid inflow pipe 13 is provided with a laser Doppler velocimeter (LDV) 20 that measures the flow speed of the liquid 11 flowing inside the pipe 13, and the flow speed V _{L, in} (t) is obtained. Then, the inflow volume velocity Q _{L, in} (t) of the liquid 11 is obtained based on the input flow velocity V _{L, in} (t) according to the above-described equation (3). In the present embodiment, the configuration combining the LVD 20 and the function of converting the flow velocity V _{L, in} (t) of the calculation unit 26 into the inflow volume velocity Q _{L, in} (t) is a flow sensor according to the present invention. Correspond.
[0045]
A sound source 21, a pressure sensor 22, and a sound pressure sensor 23 are provided on the wall of the mixing chamber 10. The pressure sensor 22 measures the static pressure of the gas 12 inside the mixing chamber 10 (or a quasi-static pressure that changes slowly compared to exp (jωt)), and the sound pressure sensor 23 measures the pressure at the angular frequency ω. It measures changes. Although the names are distinguished here, the pressure sensor 22 and the sound pressure sensor 23 may be of the same specification as long as they satisfy each application, and as long as each application is satisfied. In that case, there is only one part for directly measuring the gas pressure or sound pressure, and the pressure (static pressure or quasi-static pressure) and sound pressure (angular frequency ω) may be divided by a filter or the like.
[0046]
In the sound source 21, the surface (area A) on the inner side of the mixing chamber 10 vibrates at Q _O exp (jωt) according to the drive signal D input to the sound source. The drive signal D is input to the calculation unit 26 as a signal carrying information on the amplitude Q _O.
The pressure sensor 22 is a sensor for measuring the pressure in the mixing chamber 10 inside the gas 12, the output signal from the pressure sensor 22 is input to the low-pass filter 24, a signal indicative of static pressure or quasi pressure P _O Are extracted and input to the calculation unit 26.
[0047]
The sound pressure sensor 23 is a sensor for measuring the sound pressure P _W at the angular frequency ω of the gas 12 inside the mixing chamber 10, and the output signal from the sound pressure sensor 23 is sent to the bandpass filter 25. A signal representing the sound pressure P _W of the angular frequency ω is extracted and input to the calculation unit 26.
Data on γ _eff measured in advance in the system shown in FIG. 2 is stored in the calculation unit 26, and the calculation unit 26 stores the gas in the mixing chamber 10 based on the above-described equation (19). The volume V _G (t) is obtained.
[0048]
In this way, the calculation unit 26 obtains the inflow volume velocity Q _{L, in} (t) of the liquid 11 and the volume V _G (t) of the gas 12 inside the mixing chamber 10, and further described above (2 ), The outflow volume velocity Q _{L, out} (t) of the liquid 11 is obtained.
[0049]
【The invention's effect】
As described above, according to the present invention, the injection amount of the liquid in the injection multiphase flow can be measured separately from the injection amount of the gas.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the principle of the present invention, and is a diagram in which various symbols are added to the schematic diagram of the mixing chamber shown in FIG. 3;
FIG. 2 is a schematic view showing a state in which one embodiment of the flow measuring device of the present invention is attached to the mixing chamber shown in FIG.
FIG. 3 is a schematic view of a mixing chamber.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Mixing chamber 11 Liquid 12 Gas 13 Liquid inflow pipe 20 Laser Doppler velocimeter 21 Sound source 22 Pressure sensor 23 Sound pressure sensor 24, 25 Filter 26 Calculation part

Claims (2)

A flow rate measuring device that measures the amount of liquid ejected from a predetermined mixing chamber into which both gas and liquid flow, in a mixed phase flow in which these gas and liquid are mixed,
A flow rate sensor for measuring the flow rate of the liquid flowing into the mixing chamber;
A volume sensor for measuring the volume or volume change of the gas in the mixing chamber;
And a calculation unit for obtaining an ejection amount of the liquid in the multiphase flow based on the flow rate measured by the flow rate sensor and the volume or the volume change measured by the volume sensor. Flow measurement device. The volume sensor is
A sound source that emits sound waves including at least a predetermined frequency in the gas in the mixing chamber;
A pressure sensor for measuring the pressure in the mixing chamber;
The flow rate measuring device according to claim 1, further comprising: a sound pressure sensor that measures a sound pressure of the predetermined frequency in the mixing chamber.

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