Aerosol lidar optical layout 1- telescope, 2, 6 - photodetectors, 3 - PowerPoint PPT Presentation

Laser sensing of aerosol flows Valery G. Shemanin . Novorossiysk Polytechnic Institute, Kuban State Technological University Novorossiysk, 353900 Russia vshemanin@mail.ru 1

Abstract The main points of this work: -lidar signal for the aerosol particles, -the laser radiation spectral transmittance signal -Mie scattering indicatrix for the aerosol particles in the air flows at the various wavelengths experimental studies for -this particles concentration level and -its size distribution function measurements in our experimental conditions. All of these results show that the aerosol lidar can serve as the powerful instrument solid particles pollution monitoring in the atmospheric border layer 2 under the city area

Aerosol lidar optical layout 1- telescope, 2, 6 - photodetectors, 3 – 532 nm wavelength interference filter, 4 – lens objective, 5 – mirror R~1, 7 – glass filter, 8 – prism, 9 – laser 3

Aerosol lidar equation P ( λ , R ) = P L ( λ ) K 1 A 0 Δ RT 2 ( λ , R ) σ ( λ , R ) / R 2 , (1) P ( λ , R ) - the back scattered emission power at the wavelength λ at the ranging distance R from the distance interval Δ R ; P L ( λ ) - the laser radiation pulse power; K 1 - the lidar calibration constant; A 0 - the cross section of the receiving telescope aperture T( λ , R) = exp[ −∫ α ( λ , R) dR ] - the transmittance or transparency (2) at the wavelength λ from the lidar up to the studied volume at distance R; α ( λ , R ) – the extinction coefficient; σ ( λ , R ) = [ d σ ( λ , R )/ dn ] n(R) ] -Mie back scattering coefficient; (3) n(R) – the number concentration 4

Laser Doppler anemometer optical layout 1- RF spectrum analyzer, 2- HF filter, 3- amplifier, 4- LF filter, N  5 – counter, n  V S 6- photo detector, D 7- diaphragm,    8- objective, m m      V f 9- focusing lens,    D D T 2 sin 10- laser beam D splitter, 5 11- laser

The plot of the LDA velocity values versus MNN velocity dependence vD, m/s 10 8 6 y = 1,0197x + 0,2419 R 2 = 0,9898 4 2 0 0 2 4 6 8 10 12 vM, m/s 6 vD- LDA, vM- MMN-240 – at the number concentration of 473 1/cm3

The plot of the gravimetric data versus the LDA number concentration dependence C, g/m3 6 5 4 3 y = 4E-06x 2 + 0,0087x + 0,0573 R 2 = 0,9999 2 1 0 0 100 200 300 400 500 n, 1/cm3 C - gravimetric data, n – LDA number concentration at the aerosol flow velocity of 4.6 m/s 7

The cement particles size distribution histogram n/n0 0,6 0,5 0,4 0,3 0,2 0,1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 2r, 10 mkm S LDA 8

The plot of the cement particles Mie back scattering coefficient values versus LDA number concentration σ10e+4, 1/m 4 3 2 y = 0,0047x + 0,6455 R 2 = 0,989 1 0 0 100 200 300 400 500 n, 1/cm3 σ - lidar Mie back scattering coefficient in 10e-4 1/m, n- LDA number concentration, 9 ( d σ ( λ , R )/ dn)= (3.2 ± 0.5)10e-10 cm2 , (2.1 ± 0.6) – calc., at 532 nm laser wavelength

The closed gas pipe layout 1- electric motor, 2- fan, 3 – heater, 4- control system, 5-directing wings, 6- optical layout, 7- windows, 8, 9- photodetectors, 10- glass filters, 11,13- mechanical devices, 12- pinhole for gravimetric test, 14 – base construction, 15- tachometer 10

The plot of the cement particles mass concentration logarithm dynamics in the gas pipe lgC 5,00 4,50 4,00 y = -0,0018x + 3,3104 R 2 = 0,8197 3,50 3,00 2,50 2,00 1,50 1,00 0,50 0,00 t, s 0 200 400 600 800 1000 1200 The gas pipe cross section is 400x400 mm, the air flow velocity is about 15 m/s and 11 C- the gravimetric data in mg/m3

The plot of the cement particles mass concentration dynamics in the gas pipe 800 C, mg/m3 700 600 500 400 y = 639,5e -0,0025x 300 R 2 = 0,8348 200 100 0 0 200 400 600 800 1000 1200 t, s The air flow velocity is about 15 m/s 12

Some formulas for the cement particles air flow spectral transmittance and Mie scattering indicatrix   2 d f ( d ) dd     I I exp( D ) I exp( K l )   3 C 0 0   m 0 K     2 d 3       d f ( d ) dd K n Q ( , m ) n  4 0   D 3 C l /( ) m 32      I ( ) I ( d , m , , ) f ( d ) dd р    2 3 ( ) I   0 I ( ) I VC       0 ð m I ( ) d 3 2 4 R  р 3 d f ( d ) dd  4 0 13

The optical layout of the cement particles Mie scattering indicatrix and spectral transmittance values measuring instrument   U ( ) ( ) D U  0 ref  ex 1  0 ln[ ]   D U ( ) U ( )  ex 0 ref 1 1   Q ( , , n )    32 0 F ( )   01 32 Q ( , , n ) 32 1 1- laser, 2- glass filters, 3, 4 - mirror 5, 9, 11- photo detectors, 7- air pipe, 8- aerosol flow, 10- directing mechanical device, 12- the recording and control system 14

The plot of the cement particles scattering indicatrix in the angle range of 5 – 170 degrees Ix, arb.u. 3,5 y = 0,0001x 2 - 0,0356x + 3,314 3,0 R 2 = 0,9767 2,5 2,0 1,5 1,0 0,5 0,0 0 30 60 90 120 150 180 Teta, degrees 15 The flow velocity is 15 m/s, 650 nm laser radiation wavelength

The plot of the cement particles scattering signal dynamics at the angle of 70 degrees 14,00 Ufs, V 12,00 10,00 8,00 6,00 y = 8,0558e -0,0023x 4,00 R 2 = 0,9593 2,00 0,00 0 200 400 600 800 1000 1200 t, s The flow velocity is 15 m/s, 650 nm laser radiation wavelength 16

The plot of the cement particles air flow optical density signal dynamics at the optical length of 40 cm and 650 nm wavelength D 0,35 0,30 0,25 0,20 0,15 y = 0,2143e -0,0023x R 2 = 0,9372 0,10 0,05 0,00 0 200 400 600 800 1000 t, s 1200 17 The optical length is 40 cm, 650 nm wavelength

The plot of the cement particles air flow optical density signal logarithm dynamics lgD 0,000 0 200 400 600 800 1000 1200 -0,500 -1,000 -1,500 -2,000 y = -0,001x - 0,669 R 2 = 0,9372 -2,500 t, s The optical length is 40 cm, 650 nm wavelength 18

The plot of the cement particles scattering signal values at the 70 degrees versus mass concentration dependence 9 Ufs, V 8 7 6 5 4 y = 0,0063x + 1,1554 3 R 2 = 0,9272 2 1 0 C, mg/m3 0 200 400 600 800 1000 The flow velocity is 15 m/s, 650 nm laser radiation wavelength 19

The plot of the cement particles air flow optical density values versus mass concentration dependence D 0,50 0,45 0,40 0,35 0,30 0,25 0,20 y = 4E-05x + 0,0768 0,15 R 2 = 0,9255 0,10 0,05 0,00 0 2000 4000 6000 8000 C, mg/m3 10000 20 The optical length is 40 cm, 650 nm wavelength

The plot of the cement particles extinction efficiency average values ratio versus its average volume-square sizes Q 1,4 y = -1,4885x 2 + 2,865x - 0,2261 1,2 R 2 = 0,9974 1 y = -0,878x 2 + 1,578x + 0,3131 0,8 R 2 = 0,9982 0,6 0,4 0,2 0 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 d32 Q(650)/Q(532) Q(650)Q(405) δ 32 – the volume-square middle size in mkm; Q(650)/Q(532) and Q(650)Q(405) - 21 extinction efficiency average values ratio at the pair of laser radiation wavelengths

The plot of the cement particles optical density D(650)/D(405) ratio and extinction efficiency average values ratio Q(650)Q(405) dynamics 1,2 Q1/Q2 D1/D2 1 0,8 y = -0,3139Ln(x) + 2,8072 R 2 = 0,938 0,6 0,4 0,2 y = -0,3716Ln(x) + 3,1983 R 2 = 0,9831 0 0 500 1000 1500 2000 2500 t,s – Q(650)Q(405) calc., D(650)/D(405) – exp. 22

The plot of the logarithm normal distribution function maximum versus d32 dependence ro, mkm 0,5 y = 0,8564x + 0,0786 R 2 = 0,986 0,4 0,3 0,2 0,5 d32, mkm 0,2 0,3 0,4 R0 and d - in mkm; 120 probes 23

The plot of the cement particles logarithm normal distribution function half width versus d32 dependence Sigma y = -1,4037x + 0,8996 0,6 R 2 = 0,8503 0,5 0,4 0,3 0,2 0,1 0 0,2 0,3 0,4 0,5 d32, mkm Sigma and d32 - in mkm; 120 probes 24

The plot of the cement particles size logarithm normal distribution function and real distribution function 3 A, arb.u. 2,5 2 1,5 1 0,5 0 0 0,2 0,4 0,6 0,8 1 1,2 1,4 d, mkm LNL No.7 d - in mkm; Probe No.7 25

The plot of the cement particles size distribution dynamics in air flow 1,2 A, arb.u. 1 0,8 0,6 0,4 0,2 0 -1,5 -1 -0,5 0 0,5 1 1,5 2 2,5 -0,2 lgd 0 10 20 50 d - in mkm; 0, 10, 20 and 50 s – the time moment from the aerosol injection 26

The plot of the cement particles size distribution function in air pipe 1,4 A, arb.u. 1,2 1 0,8 0,6 0,4 0,2 0 -1,5 -1 -0,5 0 0,5 1 1,5 -0,2 lgd F-exp F-100 d - in mkm; F-100 s – the time moment from the aerosol injection, F-ext – at the enter of the filter 27

The plot of the cement particles size distribution dynamics in air pipe 3 A, arb.u. 2,5 2 1,5 1 0,5 0 -1 -0,8 -0,6 -0,4 -0,2 0 0,2 0,4 -0,5 lgd F-3600 F-exp d - in mkm; F-3600 s – the time moment from the aerosol injection, 28 F-ext – at the exit of the filter