JPH0756471B2 - Simultaneous measurement of particle velocity, diameter and refractive index by laser multifocal method - Google Patents
Simultaneous measurement of particle velocity, diameter and refractive index by laser multifocal methodInfo
- Publication number
- JPH0756471B2 JPH0756471B2 JP63242180A JP24218088A JPH0756471B2 JP H0756471 B2 JPH0756471 B2 JP H0756471B2 JP 63242180 A JP63242180 A JP 63242180A JP 24218088 A JP24218088 A JP 24218088A JP H0756471 B2 JPH0756471 B2 JP H0756471B2
- Authority
- JP
- Japan
- Prior art keywords
- refractive index
- diameter
- reflection
- detector
- particle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000002245 particle Substances 0.000 title claims description 36
- 238000005259 measurement Methods 0.000 title claims description 13
- 238000000034 method Methods 0.000 title claims description 9
- 230000000737 periodic effect Effects 0.000 claims description 15
- 230000001934 delay Effects 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 2
- 230000003287 optical effect Effects 0.000 description 5
- 101000878457 Macrocallista nimbosa FMRFamide Proteins 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000005305 interferometry Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Landscapes
- Length Measuring Devices By Optical Means (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Description
【発明の詳細な説明】 この発明は,ディーゼルなどの燃料噴霧,農業のスプレ
イ,各種工業プロセスで粒子の速度,径,屈折率を同時
に測定する装置に関するものである。Description: TECHNICAL FIELD The present invention relates to an apparatus for simultaneously measuring the velocity, diameter and refractive index of particles in fuel spray such as diesel, spraying of agriculture, and various industrial processes.
これまで,レーザ・ドップラ速度計のvisibility法や位
相測定法を用いて流れの中の粒子の速度,径を求めるこ
とが,試みられてきた。光学系の調整が難しいこと,2光
束干渉法を用いているので,信号が正弦波状となり,S/N
比が悪いこと,特に粒径が大きくなるとvisibiltyが劣
化する。縞間隔を大きくとれないため,粒子の速度,径
測定のダイナミックレンジが小さくなるなどの問題があ
った。So far, attempts have been made to obtain the velocity and diameter of particles in a flow by using the visibility method and phase measurement method of a laser Doppler velocimeter. Since the optical system is difficult to adjust and the two-beam interferometry is used, the signal becomes sinusoidal and S / N
If the ratio is poor, especially if the particle size is large, vivibilty deteriorates. Since the fringe spacing cannot be made large, there were problems such as the particle velocity and the dynamic range of diameter measurement becoming smaller.
本特許で用いる多焦点法は,測定体積中にレーザ多焦点
(2焦点以上を)作製して測定にもちいるものである。
本特許のシステムの多焦点法では,回折格子の多重干渉
を用いて,測定域に鮮鋭な干渉縞(多焦点)を作製して
いるので,S/N比の高い信号が得られる。この光学系は,
セルフアライニングで調整が容易である。縞間隔(焦点
間隔)も回折格子のピッチを変えることにより,広い範
囲で変えることが出来る。粒子の速度と径の測定のダイ
ナミックレンジが大きい。従来不可能であった粒子の径
と屈折率変化も同時測定できる特色などをもつ。The multifocal method used in this patent is used for measurement by making laser multifocal (two or more focal points) in a measurement volume.
In the multifocal method of the system of this patent, sharp interference fringes (multifocal) are produced in the measurement region by using the multiple interference of the diffraction grating, so that a signal with a high S / N ratio can be obtained. This optical system
Easy to adjust with self-aligning. The stripe interval (focal interval) can also be changed in a wide range by changing the pitch of the diffraction grating. Large dynamic range for particle velocity and size measurements. It has the feature that it can measure the particle diameter and the refractive index change at the same time, which was impossible in the past.
このシステムの光学系を図1に示す。レンズ11,12を通
り,ビーム径を拡大したレーザビームは,レンズ13の前
側焦平面に置かれた回折格子d.g.を通り回折し,レンズ
13によってそれぞれの回折光は平行になる。この後側焦
平面に集光された鮮鋭な多重干渉縞(多焦点)を測定に
用いる。できるだけ,明るい,強度のそろった多焦点を
得るため,回折格子d.g.には,パルス幅変調された位相
回析格子を用いている。反射光,屈折光を検出器PD1,PD
2で受光する。途中のアパーチャa1,a2は,多焦点の中心
軌道を粒子が通った時のみを選択するため,および一定
の立体角のみの光を抽出するため使用している。検出器
PD1,PD2は,中心軸と多焦点光線を含む同一平面上で,
中心軸から2つの異なる見込み角に配置する(この平面
から任意角度に傾けた面に配置してもよく,この場合は
後述の粒子径と屈折率の算出の際に,余弦関係を考慮し
て算出する)。この2つの検出器の使用は,後述の粒子
による反射,屈折の4つの周期信号をえるためのもの
で,異なる見込み角をとることにより,ある粒子径で屈
折により生じる信号と反射により生じる信号が,重なる
場合が生じたとき,検出器のどちらかの信号が重ならな
いようにするためである。また回析の影響を除くため,
中心軸から30度以上の見込み角に配置する必要がある。The optical system of this system is shown in FIG. Passes through a lens 1 1, 1 2, laser beam expanding the beam diameter, and passes the diffraction grating dg placed on the front side focal plane of the lens 1 3, lens
1 3 makes each diffracted light parallel. The sharp multiple interference fringes (multifocal) focused on the rear focal plane are used for measurement. In order to obtain as bright and as many multifocals as possible, a pulse width modulated phase diffraction grating is used for the diffraction grating dg. Reflected and refracted light detectors PD1, PD
Receive light at 2. Apertures a1 and a2 on the way are used to select only when particles pass through the multifocal center orbit and to extract light with a certain solid angle. Detector
PD1 and PD2 are on the same plane including the central axis and the multifocal rays,
Arranged at two different angles from the central axis (may be arranged on a plane tilted at an arbitrary angle from this plane. In this case, consider the cosine relation when calculating the particle diameter and refractive index described later. calculate). The use of these two detectors is to obtain four periodic signals of reflection and refraction by particles, which will be described later. By taking different angles of view, a signal generated by refraction and a signal generated by reflection at a certain particle diameter can be obtained. This is to prevent signals from either of the detectors from overlapping when overlapping occurs. Also, in order to remove the influence of diffraction,
It is necessary to place it at an angle of view of 30 degrees or more from the central axis.
粒子の速度Vは,多焦点を粒子がよぎった時生じる反射
光から得られる信号の周期と多焦点の各焦点間隔から求
めることができる。粒子の径と屈折率の測定原理を図2
に示す。図2では,説明上,わかり易くするため,多焦
点の1点についてのみ示してある。(a)に示すように
粒子が,ビームを通過する時,(b)に示すように,ま
ず,反射光が検出器PD2で観測され,引き続いて屈折光
がPD1で,屈折光がPD2,反射光がPD1で観測される。した
がって,PD1と,PD2で得られた信号の時間遅れT2,T1を測
定すれば,反射と屈折のスネルの法則を用いて,幾何学
的に粒子の径と屈折率を求めることができる。この方法
は,信号の強度の絶対値測定の必要がなく,時間遅れの
みを測定すればよく,較正の必要がなく,簡単に精度よ
く粒子の速度,径,屈折率の同時測定ができる特色など
がある。図2(b)の2つの時間遅れを求める時の粒子
とPD1,PD2の幾何学的関係を図3に示す。図3(a)はT
1を求める時のもので,粒子の中心が焦点レーザビーム
からhθ2の距離にある時,PD2に反射光が入り,それから
粒子が移動し,粒子の中心が焦点レーザビームからhθ1
の距離にある時,PD1に反射光が入る。図3(b)はT2を
求める時のもので,粒子の中心が焦点からlθ1にある
時,PD1に屈折光が入り,それから粒子が移動し,粒子の
中心が焦点レーザビームからhθ1の距離にある時PD1に
反射光が入る。屈折率mと径dは,図3に示すPD1,PD2
の粒子との幾何学的関係から,反射,屈折のスネルの法
則を用いて誘導した次式から算出する。The particle velocity V can be obtained from the period of the signal obtained from the reflected light generated when the particle crosses the multifocal point and each focal point of the multifocal point. Figure 2 shows the measurement principle of particle diameter and refractive index.
Shown in. In FIG. 2, only one multifocal point is shown for the sake of clarity. When the particles pass through the beam as shown in (a), first, as shown in (b), the reflected light is observed by the detector PD2, and subsequently the refracted light is PD1, the refracted light is PD2, and the reflected light is PD2. Light is observed on PD1. Therefore, if the time delays T 2 and T 1 of the signals obtained at PD1 and PD2 are measured, the particle diameter and refractive index of the particles can be geometrically obtained using Snell's law of reflection and refraction. . This method does not need to measure the absolute value of the signal intensity, only the time delay needs to be measured, does not require calibration, and features such as simultaneous and accurate measurement of particle velocity, diameter, and refractive index are available. There is. FIG. 3 shows the geometrical relationship between the particles and PD1 and PD2 when the two time delays of FIG. 2 (b) are obtained. Figure 3 (a) shows T
1 is obtained, and when the center of the particle is at a distance of h θ2 from the focused laser beam, the reflected light enters PD2 and then the particle moves, and the center of the particle moves from the focused laser beam to h θ1.
At the distance of, reflected light enters PD1. Obtained when FIG. 3 (b) to determine the T 2, when the center of the particle from the focus to l .theta.1, PD1 to contain the refracted light, then the particle moves, h the center of the particle from the focus laser beam .theta.1 The reflected light enters PD1 at the distance of. Refractive index m and diameter d are PD1 and PD2 shown in FIG.
It is calculated from the following equation derived from Snell's law of reflection and refraction from the geometrical relationship with the particles of.
d=2VT1/〔x(θ1)+x(θ2)〕 (1) m=[(T2/T1)×(x(θ1)+x(θ2))−x
(θ1)]/ cos[cos-1{(T2/T1)×(x(θ1)+x(θ2)) −x(θ1)}+2θ1] (2) ここで,x(θ1)=[2(1−cosθ1)]-1/2sin
θ1,x(θ2) =[2(1−cosθ2)]-1/2sinθ2。d = 2VT 1 / [x (θ 1 ) + x (θ 2 )] (1) m = [(T 2 / T 1 ) × (x (θ 1 ) + x (θ 2 )) − x
(Θ 1 )] / cos [cos −1 {(T 2 / T 1 ) × (x (θ 1 ) + x (θ 2 )) −x (θ 1 )} + 2θ 1 ] (2) where x ( θ 1 ) = [2 (1-cos θ 1 )] −1/2 sin
θ 1 , x (θ 2 ) = [2 (1-cos θ 2 )] −1/2 sin θ 2 .
実際に粒子の速度,径,屈折率を求める方法を具体的に
下記に示す。PD1とPD2で検出される信号例を図4(縦軸
は信号電圧I,任意目盛り;横軸は時間t,800μs/div)に
示す。測定のモデル実験としておこなったもので,粒子
の代わりに試料として,直径4.07mmガラスシリンダを回
転円板にとりつけたものを使用した。多焦点の各焦点間
隔は0.789mmであった。回折の影響を除くため,検出器P
D1,PD2の見込み角を30度以上にし,屈折信号と反射信号
の重なる場合の影響を除くため,異なる見込み角度θ1
=30度,θ2=40度とした。PD1に対しては上側に示す
2つの周期信号,PD2に対しては下側に示す2つの周期信
号,合わせて4つの周期信号が得られる。上側のPD1の
信号では,最初に振幅の大きな7つのピークをもつ屈折
による周期信号Aが現れ,次に振幅の小さな7つのピー
クをもつ反射による周期信号Bが現れる。下側のPD2の
信号では,最初に振幅の小さな7つのピークをもつ反射
による周期信号Cが現れ,次に,振幅の大きな7つのピ
ークをもつ屈折による周期信号Dが現れる。速度Vは,1
例としてPD1の振幅の大きい最初の屈折による信号Aか
ら図に示すように周期Tpを求め,(多焦点の各焦点間
隔)/(図4の周期信号の周期Tp)から算出する。図2
(b)に簡略的に示した信号の時間遅れに対して,図4
の信号から時間遅れT2,T1を求める。T2は上側にPD1の信
号の屈折による周期信号Aの最大のピークAmとPD1の信
号の反射による周期信号Bの最大のピークBmとの時間間
隔から求める。T1は下側のPD2の信号の反射による周期
信号Cの最大ピークCmと上側のPD1の信号の反射による
周期信号Bの最大ピークBmの時間間隔から求める。求め
た時間遅れT2,T1を,すでに求めた速度Vとともに式
(1),(2)に代入すれば屈折率m,径dを算出でき
る。The method for actually determining the particle velocity, diameter, and refractive index is shown below. An example of signals detected by PD1 and PD2 is shown in FIG. 4 (the vertical axis is the signal voltage I, arbitrary scale; the horizontal axis is time t, 800 μs / div). This was performed as a model experiment for measurement. Instead of particles, a sample with a 4.07 mm diameter glass cylinder mounted on a rotating disk was used. The focal length of each multifocal point was 0.789 mm. Detector P to eliminate the influence of diffraction
D1, a visual angle of PD2 by more than 30 degrees, to eliminate the impact of overlapping refraction and reflected signals, different prospective angle theta 1
= 30 degrees and θ 2 = 40 degrees. Two periodic signals shown on the upper side for PD1 and two periodic signals shown on the lower side for PD2, that is, four periodic signals in total are obtained. In the signal of PD1 on the upper side, the periodic signal A by refraction having seven peaks with large amplitude first appears, and then the periodic signal B by reflection with seven peaks with small amplitude appears. In the signal of PD2 on the lower side, the periodic signal C due to reflection having seven peaks with small amplitude first appears, and then the periodic signal D due to refraction having seven peaks with large amplitude appears. Speed V is 1
As an example, the period T p is obtained from the signal A by the first refraction having a large amplitude of PD1 as shown in the figure, and is calculated from (each focal interval of multifocal point) / (period T p of the periodic signal in FIG. 4). Figure 2
The time delay of the signal schematically shown in FIG.
Time delays T 2 and T 1 are obtained from the signal of. T 2 is calculated from the time interval between the maximum peak A m of the periodic signal A due to the refraction of the PD1 signal and the maximum peak B m of the periodic signal B due to the reflection of the PD1 signal. T 1 is obtained from the time interval between the maximum peak C m of the periodic signal C due to the reflection of the lower PD2 signal and the maximum peak B m of the periodic signal B due to the reflection of the upper PD1 signal. By substituting the obtained time delays T 2 and T 1 into the equations (1) and (2) together with the velocity V already obtained, the refractive index m and the diameter d can be calculated.
図1は,レーザ多焦点法による粒子の速度,径,屈折率
の同時測定システムの光学系,図2は,粒子の径と屈折
率同時測定の原理図。(a)は光学系,(b)は信号処
理系。図3は検出器と粒子の幾何学的関係を示す図。図
4は観測される代表的な信号パターン。Fig. 1 shows the optical system of the simultaneous measurement system of particle velocity, diameter, and refractive index by laser multifocal method. Fig. 2 shows the principle of simultaneous measurement of particle diameter and refractive index. (A) is an optical system, (b) is a signal processing system. FIG. 3 is a diagram showing a geometrical relationship between a detector and particles. Figure 4 shows the typical signal pattern observed.
Claims (1)
みの光を抽出する第1および第2の検出器を用い,該検
出器を中心軸から2つの異なる見込み角に配置し,多焦
点部のレーザビームに粒子を通過させ,その際生じる反
射光,屈折光のうち,上記2つの見込み角方向の反射光
と屈折光を受光し,第1の検出器,第2の検出器におい
て,それぞれ反射,屈折による4つの周期信号を発生せ
しめ,まず,それらの4つの周期信号のうちの任意の1
つの信号から周期を測定し,粒子の速度を算出し,次
に,第1検出器の屈折による信号と反射による信号の時
間遅れおよび第2検出器の反射による信号と第1検出器
の反射による信号の時間遅れを測定し,これら2つの時
間遅れと先に求めた粒子の速度を用いて,粒子の径と屈
折率を算出することを特徴とする粒子の速度,径,屈折
率の同時測定方法。1. In a laser multifocal method, first and second detectors for extracting light having a fixed solid angle are used, and the detectors are arranged at two different viewing angles from a central axis to obtain a multifocal lens. Of the reflected light and refracted light generated by passing particles through the laser beam of the above-mentioned part, and receiving the reflected light and refracted light in the above-mentioned two angles of view, the first detector and the second detector, It generates four periodic signals by reflection and refraction, and first, any one of these four periodic signals is generated.
The period is measured from two signals, the velocity of the particle is calculated, and then the time delay of the signal due to the refraction and reflection of the first detector and the signal due to the reflection of the second detector and the reflection of the first detector Simultaneous measurement of particle velocity, diameter, and refractive index, which is characterized by measuring the signal time delay and using these two time delays and the previously obtained particle velocity to calculate the particle diameter and refractive index. Method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63242180A JPH0756471B2 (en) | 1988-09-27 | 1988-09-27 | Simultaneous measurement of particle velocity, diameter and refractive index by laser multifocal method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63242180A JPH0756471B2 (en) | 1988-09-27 | 1988-09-27 | Simultaneous measurement of particle velocity, diameter and refractive index by laser multifocal method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0290037A JPH0290037A (en) | 1990-03-29 |
JPH0756471B2 true JPH0756471B2 (en) | 1995-06-14 |
Family
ID=17085499
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JP63242180A Expired - Fee Related JPH0756471B2 (en) | 1988-09-27 | 1988-09-27 | Simultaneous measurement of particle velocity, diameter and refractive index by laser multifocal method |
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JP (1) | JPH0756471B2 (en) |
Cited By (2)
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---|---|---|---|---|
KR20190017163A (en) * | 2017-08-10 | 2019-02-20 | 한국광기술원 | Apparatus And Method For Characteristic Mesurement Of Waterjet |
US20220364930A1 (en) * | 2019-10-25 | 2022-11-17 | Horiba, Ltd. | Radiation thermometer, temperature measurement method, and temperature measurement program |
Families Citing this family (6)
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---|---|---|---|---|
JP2770800B2 (en) * | 1995-09-20 | 1998-07-02 | 日本電気株式会社 | Dust detector |
WO2008044676A1 (en) * | 2006-10-06 | 2008-04-17 | Sumitomo Metal Industries, Ltd. | Plug member and attachment/detachment device for the same |
US8373858B2 (en) * | 2008-12-10 | 2013-02-12 | Livermore Instruments, Inc. | System and method for real time determination of size and chemical composition of aerosol particles |
CN104697454B (en) * | 2015-03-23 | 2017-06-23 | 苏州江奥光电科技有限公司 | A kind of filament diameter measuring method and device based on double grating |
CN109932304B (en) * | 2019-03-12 | 2024-03-26 | 浙江大学 | Method and device for measuring refractive index of liquid drop based on digital coaxial holography |
CN109855552A (en) * | 2019-03-16 | 2019-06-07 | 南京华群光电技术有限公司 | The two-way contactless Wire diameter measurer of one kind and method |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63201554A (en) * | 1987-02-17 | 1988-08-19 | Canon Inc | Particle analyzing device |
-
1988
- 1988-09-27 JP JP63242180A patent/JPH0756471B2/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20190017163A (en) * | 2017-08-10 | 2019-02-20 | 한국광기술원 | Apparatus And Method For Characteristic Mesurement Of Waterjet |
US20220364930A1 (en) * | 2019-10-25 | 2022-11-17 | Horiba, Ltd. | Radiation thermometer, temperature measurement method, and temperature measurement program |
Also Published As
Publication number | Publication date |
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JPH0290037A (en) | 1990-03-29 |
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