Applies To Product(s): AutoPIPE, Version(s): 2004, XM, & V8i Environment: N/A Area: Calculations Subarea: Original Author: Bentley Technical Support Group Comments, Questions, and Answers about calculations in Bentley PULS Item #1: **Attention** Please see the following AutoPIPE help section: Help > Contents> Reference> This page provides references used in the creation of the program. Item #2: How to calculate liquid pump according to help file of puls. could you provide some instruction on how to make liquid pump model and check it? could puls support liquid's model building and checking? Answer: PULS does not have a centrifugal pump. If they have to model it I would use a pipe or reducer or something to simulate volume or length. Noise cannot be simulated from centrifugal pump. If you have to, you may try a velocity source at a dead end near the pump. You may create a fictitious short branch and add a velocity source at the dead end. For reciprocating pump you can choose the recip boundary condition and works the same way as recip compressor. We have two pump examples pumpsuc and pumpfix and they are documented in the comparison to experiment and on chapter on liquid modeling in the PDF manual. Item #3: Formula used by the software to predict the shaking force amplitude in a straight pipe section, i.e. due to unbalanced forces across the pipe length. Answer: Sum(Pi x Ai). Where P and A are the pressure and area at the nodes specified in the shaking force. Item #4: our client has specifically asked for the formula used by the software to predict the shaking force amplitude in a straight pipe section, i.e. due to unbalanced forces across the pipe length. I can guess this from first principles but they have specifically requested the specific equation used by the software, (I assume based on pressure peak, cross section area etc). Answer: Sum(Pi x Ai). Where P and A are the pressure and area at the nodes specified in the shaking force. Item#5 My question was regarding the valve fluttering as seen in the PV card and flow rate calculations not matching the Ariel performance program. I updated the pressure units. Before I was entering psig and now I have updated all my pressure inputs to psia. This seems to alleviate some of the problems I was having regarding the PV card valve chatter. But the flow rates don't match the Ariel performance program. Answer: Ariel diagram does not account for pressure pulsation on piping side since it does not have that information. PULS adds pulsation at the valve node to show its effect on compressor performance. The more pulsations the more power loss and PULS computes this loss and displays that in the output report. Flow rates calculated by PULS assume 100% efficiency. Usually PULS flow rates are higher b about 10% or so. Item #6 Q1. Does Puls requires Standard Thermodynamic flow Condition or Actual Flow Condition to be input, and if it were Standard Flow Condition that are required, what standard temp and pressure are used in Puls? Q2. What about the Density, is it Standard or Actual Density to be input ? Answer: Puls requires standard flow rates to be input based on temperature = 15 deg C and pressure = 1 bar. However, Density input is based on actual values. You can manually enter actual flow rate and we recommended that you do so since PULS calculated values are usually higher than actual by about 10%. See Also Bentley AutoPIPE External Links Bentley Technical Support KnowledgeBase Bentley LEARN Server Comments or Corrections? Bentley's Technical Support Group requests that you please submit any comments you have on this Wiki article to the "Comments" area below. THANK YOU!
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