2019 ⦽ǎႊᔍᖒ⠱ʑྜྷ⦺⫭ ⇹ĥ⦺ᚁݡ⫭ םྙ᧞Ḳ
333399
Wind Tunnel Performance Test for Shrouded Probes
Ho Young Kim1,* , Maria D. King2, John S. Haglund2, and Ahmed A. Kalbasi2
1
LabWorks Inc., 19-5, Cheomdan venture so-ro 38beon-gil, Buk-gu, Gwangju, Republic of Korea
2
Texas A&M AgriLife Research, Suite 512, 600 John Kimbrough Blvd., College Station, TX 77843, United States
*
1. Introduction
The ANSI/HPS N13.1-1999 states that at least 50% of the 10µm AD particles present in the stack free stream must be delivered to the sample collector. For this purpose, a sampling nozzle shall have an aerosol transmission ratio within the range of 0.80 to 1.30, and also the aspiration ratio shall be within the range of 0.80 to 1.50 for the anticipated range of normal operating conditions or anticipated accident operational conditions for an aerosol particle size of 10ȝm AD, or for the range of sizes that could be encountered in normal or accident conditions if those sizes are greater than 10ȝm AD.[1]
This paper presents wind tunnel performance test for two types of shroud nozzles which designed and incorporated as per ANSI/HPS N13.1-1999.
2. Wind Tunnel Test for Shroud Nozzles
2.1 Shroud Nozzle and Test Facility
Test models were designed for 2 CFM suction flow by LabWorks Inc. and tests were performed at Texas A&M university. To evaluate nozzle Wall Losses, the conservative testing methods with liquid aerosols was applied.
Table 1. The shrouded and isokinetic probes
Probe RF-2-111 RF-2-112
U(m/s) 10, 15, 20 5 10, 15 Iso Nozzle ISO-1 ISO-2 ISO-1
Fig. 1. General layout of the Test Facilities (BAEN, Texas A&M University).
2.2 Definition of Nozzle Performance
There are two basic terms concerning nozzle performances: aspiration ratio(A) and wall losses (WL), are defined as A = ಮ (1) WL = ି ಮ (2) where,
ܥis the concentration at the nozzle inlet plane;
ܥஶis the aerosol concentration in the free stream; ܥis the concentration at the nozzle exit plane.
In evaluating the effectiveness of a sampling nozzle, both the A and WL should be considered. Their effects are manifested in the transmission ratio(T) as such ;
T =
340
2019 ⦽ǎႊᔍᖒ⠱ʑྜྷ⦺⫭ ⇹ĥ⦺ᚁݡ⫭ םྙ᧞Ḳ2.3 Aerosol Generation and Measurements of Free Stream Aerosol Concentration
Experiments were performed with mono-disperse liquid oleic acid aerosol particles with sodium fluorescent tracer generated by the VOAG TSI Model 3450 and introduced into the wind tunnel flow. Flattening effects for aerosols are considered.[2]
Basically free stream aerosol concentration was measured by isokinetic nozzle and the shroud probe test model was mounted isoaxially at the middle section of the wind tunnel(20cm apart in parallel between two test nozzles).
2.4 Calculation of Nozzle Performance Factors
Shroud nozzle performance were calculated using following equations : T = ǡೞೝ ǡೞାೢǡೞ (4) A = ǡೞೝାೢǡೞೝ ǡೞାೢǡೞ (5) WL = ೢǡೞೝ ǡೞೝାೢǡೞೝ (6)
where, subscripts 'spr' and 'iso' are used for shrouded and isokinetic probes respectively.
2.5 Test Results
Fig. 2 show summarized test results for two shroud nozzles. Aspiration ratio and Transmission ratio which incorporated Wall Losses are presented.
Fig. 2. Summary of the Aspiration and Transmission Ratio values for RF-2-111( ) and RF-2-112 ( ).
3. Conclusion
Test results show that LabWorks ,QF¶Vcommercial shroud nozzle(RF-2-111 and l12) meet acceptance criteria for the performance in accordance with ANSI/HPS N13.1-1999 requirements. Wall losses are 10.5~23.0% for 111 and 7.8~16.2% for RF-2-112. The measured whole data shows COV is lower than twenty (20)% of its allowable limits.
REFERENCES
>@ $16,+36 1 ³6DPSOLQJ DQG 0RQLWRULQJ Releases of Airborne Radioactive Substances IURPWKH6WDFNVDQG'XFWVRI1XFOHDU)DFLOLWLHV´ HPS (1999).
[2] )DXONQHU :% DQG - 6 +DJOXQG ³)ODWWHQLQJ Coefficients for Oleic Acid Droplets on Treated *ODVV 6OLGHV´ Aerosol Science and Technology, 46(7), 828-832 (2012).
