HW1CASE4 - EML 3005:Homework #1, SOLUTION, Nagaraj Arakere...

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Unformatted text preview: EML 3005:Homework #1, SOLUTION, Nagaraj Arakere CASE 4: Hot Day (heat soak) (Oil inlet temp = 240F, 800 rpm) Select Journal Radius (Inch), Length (Inch), Load (lbf), and Oil Inlet Temp (F) r := 0.75 2 L := .75 W := 51.0 T1 := 240.0 rpm := 800 Define Radial Clearance Range (0.0002 - 0.003 inch) c := 0.0002 , 0.0004 .. 0.0022 Define Journal Speed (rev/sec) N := rpm 60 Define Average Oil Temperature (F), i.e., Tavg = T1 + DT/2 (Guess on oil DT, and iterate on calculated value) DTGUESS( c) := 25⋅ 0.0002 c 1.2 T( c) := T1 + DTGUESS( c) 2 Define Viscosity (Reyns) vs. Temp for 10W30 oil µ ( c) := 0.7323⋅ T( c) − 2.4735 Define Unit Load Capacity (P) P := W 2⋅ L⋅ r Define Sommerfeld Number (S) as a function of clearance (c), since c is a design variable r 2 N S( c) := ⋅ µ ( c) ⋅ P c Define bearing performance parameters in terms of curve fits provided (a) Min Film Thickness, ho ho( c) := c⋅ 0.0247 + 4.2606⋅ S( c) − 10.2144⋅ S( c) + 11.4556⋅ S( c) − 4.664⋅ S( c) ( 2 3 4 ) (b) Friction Factor, f f( c) := c r ⋅ 0.7316 + 18.9931⋅ S( c) + 0.1877⋅ S( c) ( 2 ) 2 3 (c) Flow Variable Q Q( c) := ( r⋅ c⋅ N⋅ L) ⋅ 4.8281 − 4.6055⋅ S( c) + 5.9194⋅ S( c) − 2.7516⋅ S( c) ( ) (d) Side Flow Qs Qs( c) := Q( c) ⋅ 0.9614 − 2.6056⋅ S( c) + 3.4272⋅ S( c) − 1.6012⋅ S( c) ( 2 3 ) CASE 1 Calculate Oil Temp Rise DT( c) := 0.103⋅ P 1 − 0.5⋅ Qs( c) c Q( c) ⋅ r ⋅ f( c) Q ( c) ( r⋅ c⋅ N⋅ L) Print the variable values c= 2·10-4 4·10-4 6·10-4 8·10-4 0.001 0.0012 0.0014 0.0016 0.0018 0.002 0.0022 S( c) = 0.4327 0.11603 0.05268 0.02993 0.01926 0.01343 0.00989 0.00758 0.006 0.00487 0.00403 ho( c) = 1.44079·10-4 1.59441·10-4 1.33458·10-4 1.14689·10-4 1.03061·10-4 9.61047·10-5 9.21806·10-5 9.02933·10-5 8.98269·10-5 9.03862·10-5 9.17082·10-5 f( c) = 0.00479 0.00313 0.00277 0.00277 0.00293 0.00316 0.00343 0.00374 0.00406 0.00439 0.00474 Q( c) = 0.00279 0.00655 0.01035 0.01409 0.01778 0.02145 0.02511 0.02876 0.0324 0.03604 0.03968 Qs( c) = 9.65256·10-4 0.00461 0.00863 0.01249 0.01622 0.01989 0.0235 0.02709 0.03065 0.0342 0.03773 Print Oil Temperature Rise (guess and calculated), Average Oil Temp, and oil Viscosity (Calculated DT) DTGUESS( c) = 25 10.88188 6.68951 4.73661 3.6239 2.91178 2.42004 2.06173 1.78998 1.57739 1.40692 DT( c) = 27.26827 9.68129 6.0284 4.64434 3.97526 3.60251 3.37417 3.22439 3.12094 3.04653 2.99125 Avg oil temp T( c ) = 252.5 245.44094 243.34476 242.36831 241.81195 241.45589 241.21002 241.03087 240.89499 240.7887 240.70346 µ ( c) ⋅ 10 = 0.83694 0.89775 0.917 0.92616 0.93144 0.93485 0.9372 0.93893 0.94024 0.94127 0.94209 6 Plot Variables CASE 1 Min Film Thickness Vs. Clearance 160 150 140 130 6 ho( c) ⋅ 10 120 110 100 90 80 0.2 0.37 0.53 0.7 0.87 1.03 1.2 c⋅ 10 3 1.37 1.53 1.7 1.87 2.03 2.2 Oil Temp Rise (F) Vs. Clearance 30 24 18 DT( c) 12 6 0 0.2 0.37 0.53 0.7 0.87 1.03 1.2 c⋅ 10 3 1.37 1.53 1.7 1.87 2.03 2.2 ...
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This note was uploaded on 05/19/2011 for the course EML 2005 taught by Professor Arakere during the Spring '05 term at University of Florida.

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