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Rules of Thumb for Mechanical Engineers 2010 Part 6

Tham khảo tài liệu 'rules of thumb for mechanical engineers 2010 part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Pumps and Compressors 115 p 10 Pline1 3 12 Where a detailed pulsation analysis is required several approaches may be followed. An analog analysis may be performed on the Southern Gas Association dynamic compressor simulator or the analysis may be made a part of the compressor purchase contract. Regardless of who makes the analysis a detailed drawing of the piping in the compressor area will be needed. The following equations are intended as an aid in estimating bottle sizes or for checking sizes proposed by a vendor for simple installations i.e. single cylinder connected to a header without the interaction of multiple cylinders. The bottle type is the simple unbaffled type. Example. Determine the approximate size of suction and discharge volume bottles for a single-stage single-acting lubricated compressor in natural gas service. Cylinder bore 9 in. Cylinder stroke 5 in. Rod diameter 2.25 in. Suction temp 80 F Discharge temp 141 F Suction pressure 514 psia Discharge pressure 831 psia Isentropic exponent k 1.28 Specific gravity 0.6 Percent clearance 25.7 Step 1. Determine suction and discharge volumetric efficiencies using Equations 5 and 13. Evd Ev X f rp1 k 13 rp 831 514 1.617 Zj 0.93 from Figure 5 Z2 0.93 from Figure 5 f 0.93 0.93 1.0 Calculate suction volumetric efficiency using Equation 5 Ev 0.97 - 1 1 X 1.617 1 1-28 - 1 X 0.257 - 0.03 0.823 Calculate discharge volumetric efficiency using Equation 13 Evd 1 X 0.823 1.6171 128 0.565 Calculate volume displaced per revolution using Equation 1 Pd N St X 3.1416 X D2 l 728 X 4 5 X 3.1416 X 92 l 728 X 4 0.184 cu ft or 318 cu in. Refer to Figure 3 volume bottle sizing using volumetric efficiencies previously calculated and determine the multipliers. Suction multiplier 13.5 Discharge multiplier 10.4 Discharge volume 318 X 13.5 3 308 cu in. Suction volume 318 X 10.4 4 294 cu in. Calculate bottle dimensions. For elliptical heads use Equation 14. Bottle diameter db 0.86 X volume173 14 Volume suction or discharge volume .