In the late hours at Miller-Keane Petrochemicals, sat hunched over a flickering monitor, the only source of light in the engineering bay. Before him lay a spreadsheet titled Ejector_Design_Final_v12.xls —a file that had become his personal white whale.
) of the fluid flow to dynamically scale aerodynamic efficiencies. 5. Step-by-Step Design Verification Checklist
The design process is built on three fundamental conservation principles: ejector design calculation xls fixed
Therefore, an “ejector design calculation xls fixed” most commonly refers to a . The user inputs the physical dimensions of the nozzle, mixing throat, and diffuser. The spreadsheet then calculates performance curves, showing how the entrainment ratio and flow rates will respond to off-design conditions. In fact, one ejector software description confirms: “Ejector curves at fixed ejector geometry are calculated at the design discharge pressure and an increased discharge pressure” .
At=mmCd⋅Pm⋅kR⋅Tm⋅(2k+1)k+1k−1cap A sub t equals the fraction with numerator m sub m and denominator cap C sub d center dot cap P sub m center dot the square root of the fraction with numerator k and denominator cap R center dot cap T sub m end-fraction center dot open paren the fraction with numerator 2 and denominator k plus 1 end-fraction close paren raised to the the fraction with numerator k plus 1 and denominator k minus 1 end-fraction power end-root end-fraction Cdcap C sub d = Discharge coefficient (typically between 0.95 and 0.98) 3. How to Structure Your Ejector Design XLS Spreadsheet In the late hours at Miller-Keane Petrochemicals, sat
For standard gas ejectors, the ratio of the mixing tube area to the nozzle throat area (
Rm=msmmcap R m equals the fraction with numerator m sub s and denominator m sub m end-fraction = Mass flow rate of suction fluid ( = Mass flow rate of motive fluid ( Nozzle Throat Area ( Atcap A sub t supersonic flow (which occurs when
Cr=PcPecap C r equals the fraction with numerator cap P sub c and denominator cap P sub e end-fraction Pccap P sub c = Pressure of exiting vapor ( kPak cap P a Correlation for Choked Flow
Vm=2⋅ηn⋅(kk−1)⋅R⋅Tm⋅[1−(PsPm)k−1k]cap V sub m equals the square root of 2 center dot eta sub n center dot open paren the fraction with numerator k and denominator k minus 1 end-fraction close paren center dot cap R center dot cap T sub m center dot open bracket 1 minus open paren the fraction with numerator cap P sub s and denominator cap P sub m end-fraction close paren raised to the the fraction with numerator k minus 1 and denominator k end-fraction power close bracket end-root ηneta sub n : Nozzle efficiency (typically 0.94 to 0.97) : Isentropic exponent (Specific heat ratio, : Specific gas constant ( Tmcap T sub m : Motive temperature (Kelvin) Critical Nozzle Throat Area ( Atcap A sub t For choked, supersonic flow (which occurs when