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 no. 5 
 
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 in 2012 with funding from 
 
 University of Illinois Urbana-Champaign 
 
 http://archive.org/details/mixinginturbulenOOuniv 
 
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 FIFTH QUiJtEERLY PROGRESS REPORT ON RESEARCH 
 
 ccxried out "by the 
 
 ENGINEERING EXPERIMENT STATION 
 of the 
 UNIVERSITY OF ILLINOIS 
 for 
 
 ot-.^/. 
 
 fyfftt & 
 
 THE BIOLOGICAL DEPaRT I ENT , ARMY CHEMICaL CORPS, CaMP DETRICK 
 
 on 
 
 C or. tree t DA~1S-06U~C I H-U'45 
 
 Order No, 1+7^-1 
 
 October 1» 1951 i through December 31, 1951 
 
 MIXING -IK TURBULENT FLOW 
 
 Prepared byf Arnold Kivnick 
 
 Copies: 8 - Technical Director, Biological Department 
 Canp Detrick, Frederick, Maryland 
 1 - Director, Eng, Expt. St,, Univ. of Illinois 
 1 - Chairman, Graduate Research Board, U. Of I,, 
 Chenistry Department, U, Of J« 
 20 - Files 
 
 ENGINEERING 
 LIBRARY 
 
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•^ . S MIXING III TURBULENT FLOW 
 
 I. Sunnary 
 
 The technical report on the single heated jet confined in a duct 
 has been conpleted, and will he distriouted shortly, Work is progressing 
 on the preparation of technical reports on dual isothermal jets with 
 axes at an angle to one a.nother tf the electronic systen of a hot-wire 
 anemometer and studies of turbulent transport of heat in ducts, and 
 the application of the Reichardt. hypothesis to the transport of nomen- 
 tun and nags in coaxial gas jets. 
 
 The hot-wire anenoneter has been moved to a new location in order 
 to secure an oil-free air supply. Experimental studies on calibration 
 coefficients of impact tubes are in progress, The computation of the 
 extent of coalescence of droplets in turhulent free jets has been sub- 
 mitted to the Biological Department of the Amy Chemical Corps for 
 consideration. Experimental studies on the pneumatic thermometer and 
 the high-velocity spray dryer are continuing. 
 
 The present contract expires on 31 December, 1951* Technical 
 reports now in preparation will be issued as they are completed, A 
 final summary r e port must necessarily await the completion of the 
 technical reports. 
 
 The experimental work on the high-velocity spray dryer and the 
 pneumatic thermometer will he carried to completion without additional 
 support. When the experiments are complete, they will be covered in 
 a technical report. The experiments involving impact tubes \;ill be 
 continued with support from the Office of Naval Research and the Flight 
 Research Laboratory, When the studies covered in this proposal have 
 been completed, they vail he presented as a technical report to the 
 Chemical Corps, The report covering the studies on coalescence of 
 droplets awaits the decision of the Biological Division as to whether 
 or not the recommended computation should be performed. If not , the 
 technical report covering the work done will be prepared forthwith, 
 
 II, Background 
 
 The general objective of this program has been to investigate 
 the nixing of fluid streams in turbulent jets. The free jet, the 
 enclosed jet, and intersecting jet were the cases considered. The 
 data resulting from fundamental studies were to he applied to atomi- 
 zation of liquids in gas streams and to processes involving the mixing 
 of droplets and gases in jets and ducts, accompanied by the transport 
 of momentum, heat, and mass. 
 
 T 1 1 , Progress dur ing the perio d covered "by this report 
 
 a. Dual Isotherm al Jets with Axes at an Angle to One Another 
 
 A technical report on this is in preparation , 
 
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 b, Single Heated J^t Confined in A Duct 
 
 a technical report has "been prepared, and will be distributed 
 shortly. 
 
 c. Turbul ent Transport of He at in Ducts 
 
 The foremost problen inpeding progress in this study has 
 been the presence of oil in the air stream. An attempt 
 was made to remove the oil by the use of high-pressure 
 porous ceramic filters, and by low-pressure glass-batting 
 air filters. Although the oil content was appreciably 
 reduced by these methods, the air finally produced still 
 contained too much oil to permit satisfactory operation 
 of the hot wire anemometer. Moreover, because of the 
 presence in the Air-Flow Labor.. tory of high-speed turbo- 
 superchargers which operated at a prohibitively high noise 
 level, it was decided to remove the anemometer and related 
 equipment from the Air-Flow Laboratory, and to locate in the 
 Projects Laboratory of the Bast Chemistry Building, on the 
 University Campus in Urbana, A centrifugal blower was located 
 and tested, and found to be a suitable air supply,- The anemome- 
 ter was dismantled, moved, and reassembled at its net/ site. 
 It remains now to build the ducting and flow system needed for 
 further experiments. 
 
 The technical report covering the work described in the Fourth 
 Quarterly Progress Report is being prepared by R, W, ICunstman 
 in conjunction with his doctoral dissertation. Further work 
 with the anemometer will be reported in technical reports to 
 the Office of Naval Research and the Flight Research Laboratory £ . 
 which will support this research in the coming year, 
 
 d. High-Velocity Spray D ryer 
 
 The problems of instrumentation described in the Fourth 
 Quarterly Progress Report have been attacked, and, it is 
 believed, surmounted. The measurement of humidity was 
 performed by an addition to the pneumatic thermometer 
 (cf. section e-2, Instruments), The air stream was dried 
 through a bed of magnesium perchlorate, an extremely 
 effective desiccantj and the dried stream was then passed 
 through a calibrated orifice. The humidity may be calculated 
 by the difference in the volume of the moist and dried air 
 streams. 
 
 The first drying runs, in which water droplets are evaporated^ 
 have recently been undertaken, 
 
 e. Instruments 
 
 . 1. The total head impact tube (Pitot Tube) 
 
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 The experimental program concerned with the investigation into 
 the calibration coeff icients of impact tubes has "been delayed 
 by the unforeseen occurrence of leaks in the airflow system. 
 Since these leaks were present in the part of the system between 
 the flow neter and the equipment to be used in this investigation f 
 and since the leaks were in heat exchange equipnent which could 
 neither be repaired nor renoved fron the line, it has been 
 necessary to build a new flow meter, of the orifice type, and to 
 locate it downstream of the leaks. This neter is now undergoing 
 calibration. When this work is completed, it will be possible 
 to return to the study or. impact tubes. 
 
 In the interim, the literature search has been broadened end 
 intensified, to determine whether the approach being taken in 
 this research has ever been used before. In particular , recent 
 studies are being evaluated. 
 
 The experimental program will be continued with the support pre- 
 viously mentioned, Waen that pc.rt of the research covered under 
 this contract has been completed* a technical report \idll be 
 prepared* 
 
 2. Dry 3ulb Temperature Probe ( Pneumatic Ihermometer ) 
 
 Repeated attempts to operate as critical oridices the several 
 orifices of which the pneumatic thermometer is composed have 
 failed because of lack of capacity of the pumps concerned,, In 
 order to avoid further loss of time and expense in securing a 
 suitable vacuum pump, the pumps available have been operated 
 submerged in ice, to prevent overheating and resultant severe 
 damage. Since the orifices could not be operated at the critical 
 pressure drop, it was necessary to calibrate each orifice. This 
 was done by passing an air stream tiirough one of a set of pre- 
 cision Floiiraters , and then through the orifices. 
 
 Much of the experimental work during this period has been concerned 
 with establishing the precise limits of accuracy permitted by the 
 unavoidable errors in the apparatus. As an example of the nature 
 of these errors, fourteen observations of manometers are required 
 for the determination of each point. Taking into account the error 
 inherent in each of these observations, a careful variance analysis 
 shows that the probable error in any single observation of tempera- 
 ture is 3 percent. Since the readings will be in the region of 
 1000°R.j the error will be about 30°P. out of about G00°F, However, 
 these observationr.l errors should be eliminated or materially 
 reduced by the smoothing procedures to be employed in the course 
 of operating the instrument. Although the value of any one 
 observation may vary from the true reading by as much as JO ]?, , 
 there should be far less variation in the mean value of ten such 
 readings. The variation in the mean value has been found to be a 
 
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 o. function of the variation of the orifice coefficients with the 
 gas flow rate. In evaluating the orifice coefficients; 219 separate 
 runs were performed, They indicate that the maximum variation 
 in orifice coefficients is of the order of 3 percent while the 
 standard deviation of those coefficients from their .lean value 
 is 1,5 percent.. Therefore 5 the standard deviation between 
 successive readings of temperature obtained from the pneumatic 
 thermometer should be not more than 15°i\ in 1000 R ? or 15°F C in 
 about 600 °]T- This is satisfactory precision for engineering 
 studies « 
 
 The pneumatic thermometer was further complicated by being modified 
 in order to provide a humidity measurement, A third orifice was 
 e.dded to the line. Thoroughly desiccated air is passed through 
 this last orifice and metered, and its flow rate is compared with 
 that through the second orifice; from these two flow rates, the 
 humidity of the gas flowing through the second orifice may be 
 computed, 
 
 Barring unforeseen difficulties, the pneumatic thermometer may 
 be used with reasonable assurance of accuracy within the limits 
 specified. 
 
 f , Theoretical Program 
 
 The problem of coalescence of droplets in a turbulent jet was 
 submitted to three computation laboratories, in order that esti- 
 mates might be made of the cost of computing the solution. The 
 laboratories were 'the Differential Analyzer Laboratory of the 
 University of Pennsylvania, the Punchod-Card Digital Computer 
 Laboratory of the Department of Chemical Engineering at the 
 Pennsylvania State College, and the Computer Laboratory of the 
 National Bureau of Standards, The last named group has submitted as 
 an estimate $5,000, while neither of the other groups has as 
 yet been able to decide on the probable expense* Since the funds 
 assigned to this contract are virtually exhausted, the matter of 
 the computation has been turned over to the Biological Department 
 together with all information necessary for the solution. 
 
 In the event that the Department prefers not to go ahead with the 
 computation at this time, a technical r eport on the coalescence of 
 droplets in turbulent jets will be prepared, in which the equations 
 will be presented in their final form, together with all information 
 necessary for the solution. 
 
 The extension of the Hcichardt hypothesis to the flux of momentum 
 and mass in the case of a jet issuing into a stream flowing in a 
 duct has been completed, A technical report on this subject is in 
 the last stages of preparation, and should be issued before the 
 end of January, 1°,52« 
 
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 IV, Personnel 
 
 The project has beer, under the supervision of Dr„ .am old Kivnick 
 on a full-tiue basis \ Professor H» f. Johnstone has replaced 
 Professor E, l/ Ooninga in the position of overall direction,, During 
 the period covured in this report ». C. L„ Goldren was enployod on a 
 half-tine basis, on the high— velocity spray dryer. J. E, itonano 
 worked on the hot-wire anenoneter » and 11, D. Danielson on the ir.pact--v.be 
 studies; neither of these received condensation fron the contract