Acoustic modeling of reciprocating compressor package piping
We perform acoustical analysis for reciprocating compressor piping system in accordance with Method 1, 2 and 3 of GOST 31843-2013 (ISO 13707:2000) and DA1, DA2 and DA3 of API 618 (previously M.1 - M.8)
Acoustic modeling – method that allows quantitative assessment of gas pressure pulsation in pipes and determination of forces acting on all the package piping elements causing vibration.
Acoustic modeling is required for reciprocating compressors according to standards GOST 31843-2013 (ISO 13707:2000) and API 618.
According to the specified standards, three methods can be applied, differing in scope and detail of calculations, depending on unit power and maximum discharge pressure.
- Method 1 involves selection of pulsation vessels based on empirical and simplified analytical methods. Simplified piping analysis is performed if necessary. Critical piping section lengths are determined.
- Method 2 involves development of pulsation vessels design and determination of piping support locations by modeling compressor cylinder and piping interaction. Acoustic modeling is performed.
- Method 3 involves modeling according to Method 2 with addition of piping mechanical analysis – interaction of acoustic and mechanical systems is evaluated. Displacement and vibration velocity of all piping sections including compressor cylinders are calculated.
ХЁРБИГЕРСЕРВИС performs acoustic modeling for reciprocating compressor packages with Methods 1, 2 and 3 in accordance with current regulatory requirements.
Calculation results include:
- Design of pulsation vessels, including internal structure.
- Gas pulsation amplitudes and frequencies throughout the system.
- Amplitudes and frequencies of acting forces as the result of pressure pulsation.
- Recommendations for reducing pulsation levels and forces, including drawings and locations of orifice plates and recommendations for piping layout.
- Pressure drop across pulsation vessels.
- Amplitudes and frequencies of vibration velocity/displacement at system critical sections.
- Stress values in piping caused by pressure pulsation, average operating pressure and temperature.
- Recommendations for reducing vibration and stress levels, including support drawings and their locations.
Advantages of ХЁРБИГЕРСЕРВИС:
- Specialization in reciprocating compressors: team with extensive experience of working in companies – global leaders in compressor manufacturing.
- Modeling in full compliance with current standards requirements.
- Calculation methodology, developed in collaboration with industry leading institutes and verified in practice.
- Extensive experience in diagnostics, analysis and troubleshooting of reciprocating compressor equipment.
- Long-term experience of interaction with companies specializing in acoustic modeling on the global market, analysis and application of their solutions for end customers.
Example of modeling result
Pulsation at running speed
Pulsation at 2x running speed
Pulsation at 4x running speed
Pressure pulsation values and acting forces
| Piping model point number | Maximum pulsation value, MPa | Frequency, Hz (nearest harmonic from running speed) | Allowance per API 618 and GOST 31843-2013, MPa |
|---|---|---|---|
| 103 | 0,056 | 64,6 (4x) | 0,072 |
| 1231 | 0,018 | 64,6 (4x) | 0,018 |
| 335 | 0,117 | 64,6 (4x) | 0,018 |
| 356 | 0,013 | 64,6 (4x) | 0,018 |
| 703 | 0,010 | 64,6 (4x) | 0,018 |
| 892 | 0,007 | 31,7 (2x) | 0,026 |
| 1167 | 0,0014 | 15,9 (1x) | 0,037 |
Acting force values
| Piping model section number | Maximum force value, N | Frequency, Hz (nearest harmonic from running speed) | Limit per API 618 and GOST 31843-2013, N |
|---|---|---|---|
| F1 | 1,74 | 95,0 (6x) | 1954 |
| F2 | 1,82 | 70,0 (4x) | 2250 |
| F3 | 5,62 | 31,7 (2x) | 2250 |
| F4 | 9,68 | 70,0 (4x) | 2250 |
| F5 | 5,62 | 31,7 (2x) | 2250 |
| F6 | 2,91 | 31,7 (2x) | 2250 |
| F7 | 4,07 | 31,7 (2x) | 2250 |
| F8 | 1,14 | 15,9 (1x) | 2250 |
| F9 | 1,35 | 67,8 (4x) | 2250 |
Maximum stress in piping
| # | Load type | Maximum stress, MPa | Maximum allowable stress, MPa | Section |
|---|---|---|---|---|
| 1 | Constant (gravity and max. pressure) + dynamic load | 81,41 | 156,67* | 1st stage suction cylinder flange |
| 2 | Constant (gravity and max. pressure) + Safety valve actuation | 81,57 | 180,82*** | - |
| 3 | Gas pulsation only | 3,18 | 156,67* | 1st stage cylinder flange at discharge |
| 4 | Hoop stress of pipes and vessels | 119,69 | 175,89** | All pulsation bottles, heat exchangers of 2nd and 3rd stages, gas inlet heater |
| 5 | Temperature deformations +20...-60°C | 105,68 | 180,82*** | Discharge pulsation bottle-heat exchanger of 2nd and 3rd stages |
| 6 | Temperature deformations +20...+112°C | 122,89 | 180,82*** | Discharge pulsation bottle-heat exchanger of 2nd and 3rd stages |
| 7 | Temperature deformations -60...+112°C | 220,13 | not regulated | Discharge pulsation bottle-heat exchanger of 2nd and 3rd stages |
*Adopted value: endurance limit/1.5 – lower than GOST 32388-2013 requirement, clause 5.3.1.
**According to GOST 32388-2013, clause 5.3.1.
***According to GOST 34233.1-2017, Table A.1
Stress map for pressure pulsation, maximum gas pressure and mass of pipes with contents
| Measurement point | Maximum vibration velocity, mm/s (RMS), overall level | Vibration velocity along piston axis, mm/s | Vibration velocity in vertical direction, mm/s | Vibration velocity along crankshaft axis, mm/s | Frequency, Hz | Limit, mm/s RMS |
|---|---|---|---|---|---|---|
| К05 | 12,37 | 11,95 | 0,99 | 3,04 | 66,8 | 19 |
| К08 | 10,44 | 9,96 | 2,61 | 1,73 | 66,8 | 19 |
| К13 | 8,91 | 8,57 | 0,61 | 2,35 | 66,8 | 19 |
| A08 | 3,42 | 2,57 | 2,21 | 0,45 | 105,0 | 19 |
| P11 | 4,70 | 1,29 | 0,40 | 4,51 | 96,5 | 19 |
