ME 4054: Estimation for Spring 2009Estimation TechniquesQuick ModelsQuick MeasurementsQuick MeasurementsTypical Quantities Engineers should know: EfficiencyDragQuick CalculationsOther Examples of Quick CalculationsEstimation TechniquesME 4054: Estimation for Spring 2009Estimation TechniquesLearn when to say that doesn’t sound rightQuick ModelsQuick measurementsQuick CalculationsQuick Models Rourke’s Formulas for Stress and Strain Intro to Mechanical Engineering by WickertTension = 400 lbQuick Measurements Length: hair diameter =50 micronsfoot or floor tile = 1 ft= 100 m Density/ ViscosityKnow the density and viscosity of typical fluids (order of magnitude will suffice)Quick Measurements Elastic Modulii: StrengthTypical Quantities Engineers should know: Efficiency IC engine Electric Motor Wind Turbine Solar Cell Hot Water heater Furnace15-25%80%30-50%5-15%60-65%80-95%What is the efficiency for typical energy producing systems?Drag Economy sedan at 60 mph Sports Car at 60 mph Suv at 60 mph Racing bike rider PersonRange from 0.3 to 1.20.340.290.450.91.2Quick Calculations Example Reynolds number:μρ=vlRe Round off, check units0.3 in diameter bullet at 2400 ft/sWater through a 1 cm pipe, 0.5 m/sSubmarine with full of 33ft, 15 knots5000 6.7 E7 3.7 E5bulletSubpipeOther Examples of Quick CalculationsFluids Engineering Thermal and Energy SystemsEstimation TechniquesLearn when to say that doesn’t sound rightQuick ModelsQuick measurementsQuick
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