Performance of Louvered Devices as Air MixersU.S. National Bureau of Standards, 1970 - 20 pages As part of a study evaluating methods for reducing thermal gradients within the cross section of an air stream, three louvered mixing devices were investigated. Each of these devices was found to be capable of reducing the cross-sectional nonuniformity of air temperature to a few percent of the entering value. |
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Page 1
... effectiveness level of 97 percent . The mixing effectiveness of the louvered strip and concentric louver models was independent of the approach velocity , whereas the effectiveness of the louver - baffle model was somewhat dependent on ...
... effectiveness level of 97 percent . The mixing effectiveness of the louvered strip and concentric louver models was independent of the approach velocity , whereas the effectiveness of the louver - baffle model was somewhat dependent on ...
Page 5
... effectiveness are defined by eqs ( 1 ) and ( 2 ) . 1 1/2 - [ - ] " ( 1 ) Σ S.D. = Effectiveness n - 1 S.D. where : n = = = Xi x S.D.DS S.D.Us = ( Xi 1.0 ( 1 . x ) 2 S.D.DS S.D.us × 100 % ( 2 ) number of measurements , individual ...
... effectiveness are defined by eqs ( 1 ) and ( 2 ) . 1 1/2 - [ - ] " ( 1 ) Σ S.D. = Effectiveness n - 1 S.D. where : n = = = Xi x S.D.DS S.D.Us = ( Xi 1.0 ( 1 . x ) 2 S.D.DS S.D.us × 100 % ( 2 ) number of measurements , individual ...
Page 6
... Effectiveness Range Std . * Dev . CFM in . W.G. in . Duct in . Diam . Duct Diam . in . Duct Diam . deg F % % 1 1400 0.07 12 12 0.50 102 4.25 114 4.75 3.6 90.1 92.5 2 1400 0.07 24 1.00 90 3.75 114 4.75 3.6 91.5 93.9 3 1400 0.07 36 1.50 ...
... Effectiveness Range Std . * Dev . CFM in . W.G. in . Duct in . Diam . Duct Diam . in . Duct Diam . deg F % % 1 1400 0.07 12 12 0.50 102 4.25 114 4.75 3.6 90.1 92.5 2 1400 0.07 24 1.00 90 3.75 114 4.75 3.6 91.5 93.9 3 1400 0.07 36 1.50 ...
Page 7
... Effectiveness of the louvered strip mixing device relative to the spacing between mixing elements . ( OVERALL DISTANCE : 4.75 DUCT DIAMETERS ) MEAN AIR. ( % ) 100 96.2 % 90 90.2 % 80 70 EFFECTIVENESS 50 60 50 TEMPERATURE PATTERNS 99.0 ...
... Effectiveness of the louvered strip mixing device relative to the spacing between mixing elements . ( OVERALL DISTANCE : 4.75 DUCT DIAMETERS ) MEAN AIR. ( % ) 100 96.2 % 90 90.2 % 80 70 EFFECTIVENESS 50 60 50 TEMPERATURE PATTERNS 99.0 ...
Page 8
... Effectiveness of the louvered strip mixing device as the overall distance from the inlet of the mixing device to the downstream measuring station was varied . Measurements were also made to compare the effectiveness of the mixer at two ...
... Effectiveness of the louvered strip mixing device as the overall distance from the inlet of the mixing device to the downstream measuring station was varied . Measurements were also made to compare the effectiveness of the mixer at two ...
Common terms and phrases
0.92 duct diameter 4.75 DUCT DIAMETERS air flow Air Mixers air passed AIR STREAM VELOCITY apparatus ASHRAE automatic data processing baffles blower Building Science Series Bureau of Standards cents circular band concentric louver mixing CONCENTRIC TEMPERATURE PATTERN cross section deg F Devices as Air DIAMETER DUCT FPM DIAMETERS MEAN VELOCITY direct the air DISTANCE BETWEEN MIXING downstream measuring station Duct Diam DUCT DIAMETERS MEAN duct wall elements in series evaluated FIGURE 17 flow rate held constant louver angle louver mixing device LOUVER SETTING louver-baffle mixing device louvered strip mixing MEAN AIR STREAM ment metal mixing effectiveness National Bureau normal path outer area path of flow PATTERN THREE QUADRANTS percent pitot-static tubes QUADRANT COOL QUADRANT TEMPERATURE PATTERN Resistance Thermometer shown in figure spacing between mixing standard deviation strip mixer strip mixing device tempera temperature difference TEMPERATURE PATTERN THREE test conditions THERMOCOUPLES THREE QUADRANTS WARM tion ture U.S. Government Printing velocity head
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Page 1 - A schematic of the apparatus is shown in figure 1. Figure 2 is a photograph of the apparatus.
Page 20 - Announcement of New Publications in Building Science Series Superintendent of Documents, US Government Printing Office, Washington, DC 20402 Dear Sir: Please add my name to the announcement list of new publications to be issued in the series : National Bureau of Standards Building Science Series. Name Company Address City State Zip Code (Notification key N-339...