DIESEL FUELS & DIESEL FUEL SYSTEMS

Application and Installation GuideDiesel Fuels & Diesel Fuel SystemsStep 4Calculate the heat transferred between the fuel in the day tank and theatmosphere, the ∆T of the fuel in the day tank due to the heat transfer, andthe resulting fuel day tank temperature.a. Heat transferred between the day tank and the atmosphere:(TMIX + TDT)QTK = U x [ (H x (2L + 2W) + (L x W) ] x[ TAMB - 2 ] x tWhere:QTK =Heat transfer to/fromatmosphere (Btu)This considers 6mm (0.25in.) steel plate forming thetank boundaries, and thefilm coefficient for air andoil. The air side filmcoefficient is predominantwhen compared to the oilside film. The tank thicknesshas a negligible effect.U = Coefficient of heattransfer, (0.0424 Btu/min•ft 2 •°F)L = Day tank length (ft)W = Day tank width (ft)TAMB = Ambient temperature (°F)TMIX = Mix temperature of returnfuel and fuel in tank (°F)TDT = Day tank temperatureresulting from heat transferto/from day tank (°F)T = Incremental time step(min)H = Fuel height for specifictime step (ft)b. Temperature change in the daytank resulting from heat to/fromday tank:Where:∆TDTQTKMDTCP∆ TDT =QTKMDT x Cp= Temperature change offuel in the day tank (°F)= Heat transfer to/fromatmosphere (Btu)= Mass of fuel in day tank(lb)= Specific heat of #2 MDO= 0.5 Btu/lb •°Fc. Day tank temperature resultingfrom heat transfer to/from daytank:TDT = TMIX + ∆TDTWhere:TDT = Day tank temperature(°F)TMIX = Mix temperature of returnfuel and tank fuel (°F)∆TDT = Temperature change ofday tank (°F)These three calculations areinterdependent in nature. First, QTK isdetermined for the first incremental©2005 Caterpillar®All rights reserved. Page 43