Document 32ammbKdan4w3Lj6Leww4O1O

8 CHAPTER 2 1959 Guide Area................. .......................................................................... a Change in specific volume during vaporisation.................... >*# Density, Weight per unit volume, Specific weight, .d or p (rho) Distance, linear........................ .............................. ...................* Dry saturated vapor, Dry saturated gas at saturation pres sure and temperature, vapor in contact with liquid ..................................................................................Suogcripl g Efficiency........................................................................................... Elevation above some datum................................................-s % Emissivity............................................................................ ......... ~t Energy in general; work, total; work, molal. . .............E Entropy. (The capital should be used for any weight, and the small letter for unit weight)......................... .......S or * Force, total load...................................................... .................F Gas Constant, in equation pK = nRT........... ......................R Head...................................................................................... H or h Heat content, Total heat, Enthalpy. (The capital should be used for any weight and the small letter for unit weight)............................................................................ H or h Heat content of saturated liquid. Total heat of saturated liquid, Enthalpy of saturated liquid, sometimes colled heat of the liquid.................................................................. hf Heat content of dry saturated vapor, Total heat of dry sat urated vapor, Enthalpy of dry saturated vapor.................h, Heat of vaporization at constant pressure...................L or h/f Hydraulic radius......................................................................... Internal energy, Intrinsic energy. (The capital should be used for any weight and the small letter for unit weight)............................................................................ (/ or u Length of path of heat flow, thickness............................... , Load, total................................................................................. ' `w Mechanical efficiency............................................................... e Mechanical equivalent of heat........................................... . . . J Power, Horsepower, Work per unit time................... P Pressure, Absolute pressure. Gage pressure, Force per unit area................................................................................. Quantity (total) of fluid, water, gas, heat; Quantity by volume; Total quantity of heat transferred.....................Q Quality of steam. Pounds of dry steam per pound of mix ture ......................................................................................... x Reynolds Number................................................................... ' Saturated'liquid at saturation pressure and temperature, Liquid in contact with vapor.......................... .. Subscript f Specific heat.............................................................................. c Specific heat at constant pressure......................................... Specific heat at constant volume................. ................. e Specific volume, Volume per unit weight, Voiume per unit Temperature (ordinary) F or C. (Theta is used preferabiy only when t is used for Time in the same discussion) ................................................................................. or 6 (theta) Temperature (absolute) F abs or K. (Capital theta is used preferably only when small theta is used for ordinary temperature) ,......................................T or (capital theta) Thermal conductance :4 heat transferred per (unit time) (degree)........................................................................................ C =. I -- - g R . L "h--^ Thermal conductance per unit area, Unit conductance: heat transferred per (unit time) (unit area) (degree) C ~C - -l - * _ * A RA A(l, -- I*) = L Term* ending wity designate properties independent ci size or shape, eon* times called spteifie properties. Examples: conductivity, resistivity. Terms endis one* drsicnnts quantities depending not only on the material, but also upon sis and shape, sometimes called total yuanlilies. Examples: conductance, tranzmji tones. Terms ending ion designate rats of heat transfer. Ewaplca: Thermal conductivity: heat transferred per (unit time) (unit area) (degree per unit length)...................................k S_ A * * fa - <J L Surface coefficient of heat transfer, Film coefficient of heat transfer, Individual coefficient of heat transfer: heat transferred per (unit time) (unit area) (degree)......../ A / ti- t* (In general / is not equal to k/L, where L is the actual thick ness of the fluid film.) Overall coefficient of heat transfer, Thermal transmittance per unit area: heat transferred per (unit time) (unit area) (degree overall)............................................................ y q Thermal transmission (heat transferred per unit time). __ Q Thermal resistance (degree per unit of beat transferred per unit time)..........................................................................ft q kA Thermal resistivity..................................................................... j/j Vaporization values at constant pressure, Differences be tween values for saturated vapor and saturated liq uid at the same pressure.................................... Subscript/a Velocity......................................................................................... y Viscosity, absolute................................................. p Viscosity, kinematic............................................................... ' Volume (total)..................................................... y Volume per unit time, Rate at which quantity of material passes through a machine, Quantity of heat per unit time, Quantity of heat per unitweight..............................q Weight of a major item, Total weight...................................... w Weight rate, Weight per unit of power, Weight per unit time of............. w Work (total)......................................................... jp CONVERSION EQUATIONS6 Heal, Power and Work 1 ton refrigeration Latent heat of i< ( ^tu Pec.^our \ 200 Btu per minute 143.4 Btu per pound I Btu 1 Int- watthour 1 Int. kilowatthour ________ ( 778.3 ft-lb \ 0.2930 Int. whr ( 252.0 I.T. calorie f 2656 ft-lb ) 3.413 Btu I 3600 Int. joules ( 880 I.T. calories f 3,413 Btu = < 3.517 lb water evaporated ( from and at 212 F Abbreviations, Symbols, Conversion Factors 1 Int kilowatt (1000 watts) f 1.341 hp - \ 56.88 Btu per minute { 44,267 ft-lb per minute 1000.I-T. calories! 1 I.T. kilocalorie/ 1 horsepower 1 boiler horsepower I 3088*ft-lb l 1.1628 Int. whr ! 0.7455 Int. kw 42.40 Btu per minute 33,000 ft-lb per minute 550 ft-lb per second / 33,475 Btu per hour \ 9.809 lot. kw Weight and Volume i1 gail (/tUt. cS.i) /^ o23.1133c7u cinu.ft 1 British or Imperial gallon = 277.42 cu in. 1 cu ft 7.481 gal 1728 cu in. 1 cu ft water at 60 F (in vacuo) 62.37 lb leu ft water at 212 F(" u ) = 59.83 lb 1 gal water at 60 F (" " ) = 8.338 lb 1 gal water at 212 F (" " ) = 7.998 lb 1 lb (avdp) = | 7000 grains. 1 bushel 1 short too = 1.244 cu ft = 2000 lb Pressure 1 lb per square inch 144 lb per square foot 2.0360 m. mercury at 32 F * 2.0422 in. mercury at 62 F 2.309 ft water at 62 F 27.71 in. water at 62 F 1 oz per square inch = 0.1276 in. mercury at 62 F 1.732 in. water at 62 F 1 atmosphere 14.696 lb per square inch 2116 lb per square foot = 33.94 ft water at 62 F 30.01 in. mercury at 62 F 29.921 in. mercury at 32 F 0.03609 lb per square inch (1 in. water at 62 F (in vacuo) 0.5774 oz per square inch 5.197 lb per square foot 1 ft water at 62 F (in vacuo) -- 0.4330 lb per square inch 62.37 lb per square foot 0.4897 lb per square inch i1 in. mercury at 62 F (in vacuo) = 7.835 oz per square inch 1.131 ft water at 62 F 13.57 in. water at 62 F 1 in. mercury at 32 F (in vacuo) = 0.49115 lb per square inch Metric Units 1 cm 1 in. 1m 1 ft 1 sq cm 1 sq in.1 sq m 1 sq ft 1 cu cm 1 cu in. 1 cu m -- 0.3937 in. = 0.0328 ft = 2.540 cm = 3.281 ft = 0.3048 m = 0.1550 sq in. -- 6.452 sq cm -- 10.76 sq ft = 0.09290 sq m -- 0.06102 cu in. = 16.39 cu cm " 35.31 cu ft 9 1 cu ft 1 liter 1 kg 1 lb 1 metric ton 1 gram 1 kilometer per hour 0-02832 cu m 1000 cu cm m 0.2642 gal 2.205 lb (avdp) 0.4536 kg ' 2205 lb (airdp) 0.002205 lb (avdp) . 0.6214 mpb 1 gram per square centimeter 0.02905 in. mercury at 62 F 0.3942 in. water at 62 F 1 kg per sq cm (metric at mosphere) = 14.22 ib per square inch 1 gram per cubic centimeter 0.03613 lb per cubic inch 62.43 lb per cubic foot 1 dyne = 0.00007233 poundals 1 absolute joule 10,000,000 ergs 0.7376 ft-lb 1 Int. joule = 0.7378 ft-lb 1 metric horsepower _ / 75 kg-m per second " \ 0.986 hp (U. S.) 1 I.T. kilocalorie per kilogram = 1.8 Btu per pound I I.T. calorie per square centi meter " 3.687 Btu per square foot 1 I.T. calorie per (second) (square centimeter) for a temperature gradient of 1 C deg per centimeter 2903 Btu per (hour) (square foot) for a tem perature gradientof I F deg per-inch of thick ness. GRAPHICAL SYMBOLS FOR DRAWINGS* Piping Heeling 1. High-Pressure Steam 2. Medium-Pressure Steam 3: Low-PressureSteam 4. High-Pressure Return 5. Medium-Pressure Return '6. Low-Pressure-Return 7. Boiler Blow Off 8. Condensate'or. Vacuum. Pump Discharge 9. Feedwater, ^ump Discharge 10. Make-Up Water 11. Air Relief Line 12. Fuel Oil Flow 13. Fuel Oil Return 14. Fuel Oil Tank Vent 15. Compressed Air 16. Hot Water Heating Supply 17. Hot Water Heating Return ------ if-----**- ** ----- A-->* -- -- --#------if--- iV- -- --a-------- *--------*--------------------------------------- ----------------------- --o-------O-------- o-- --oo------OO------ OO-- "1 1 1 ---------------------------------------- fof-----------------------FOR--------------------- rFOV'------------;------- -- *--------------------:--------------------------------------------------- Air Conditioning 18. Refrigerant Discharge 19. Refrigerant Suction 20. Condenser Water Flow 21. Condenser Water Return 22. Circulating-Chilled or Hot Water JPlow ------------ ro--------------------------- rs----------- --- ------ ;-------c-------------------------- cr------------- ------------ ch------------- * Extracted from: American Standard Graphical Symbols for Pipe Fittings Valvm; "A Piping (ASA ZSJ.2.S-I90) and Anerian Standard Graphical Sym bols for Htttiat. Ventilating, and Air Conditioning (ASA Z3M.H919) with the peimittioBO the publisher. The American Society of Mechanical Engineers, 29 West mb St., New York 18. N. Y.