GB/T 41890.1-2022 in English
VALIDShips and marine technology―Model test method for propeller cavitation noise evaluation in ship design―Part 1:Source level estimation
- Issued on:2022-10-12
- Implemented on:2022-10-12
- File Format:PDF
- Delivery:Via email within 1~3 business days
$243.00
| Standard No: | GB/T 41890.1-2022 |
| Document status: | VALID |
| Title in English: | Ships and marine technology―Model test method for propeller cavitation noise evaluation in ship design―Part 1:Source level estimation |
| Title in Chinese: | 船舶与海上技术 船舶设计过程中螺旋桨空化噪声模型试验方法 第1部分：声源级评估 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 1~3 business days |
| Issued on: | 2022-10-12 |
| Implemented on: | 2022-10-12 |
| ICS Classification: | 47.020.20-Marine engines and propulsion systems |
| Chinese Classification: | U40-Main and auxiliary machines for vessel in general |
| Professional Classification: | GB-National Standard |
| Related Keywords: | propeller cavitation noise evaluation
cavitation morphology ship model accuracy cavitation number marine technology ― model test method standard pressure boost method |
| Related Topics: | Chinese ships
Sound source intensity GB/T 41890.1 GB/T 41890.1-2022 for shipsmilitary Ship design acceptance technology |
《GB/T 41890.1-2022船舶与海上技术 船舶设计过程中螺旋桨空化噪声模型试验方法 第1部分：声源级评估》由TC137（全国船用机械标准化技术委员会）归口，主管部门为国家标准化管理委员会。
Introduction
Analysis of the core content of the standard
Key technologies of test configuration
| Elements | ISO20233:2018 requirements | GB/T modifications | Technical significance |
|---|---|---|---|
| Reynolds number | Undefined lower limit | ≥5×10⁵ (1×10⁶ recommended) | Ensure the similarity of cavitation morphology |
| Ship model accuracy | Total length error 0.1% | Increase cross-section line shape ≤0.5mm | Improve the simulation accuracy of the wake field |
| Installation error | Not specified | Shaft center deviation ±0.1mm | Reduce mechanical vibration interference |
Innovation requirements for noise measurement
- Pressure boost method: Keep KT/KQ unchanged but change the air content
- Hub replacement method: Maintain air content but change load characteristics
It is recommended to use the boost method first (Clause 6.2)
Data acquisition specification upgrade
- Resolution increased from 16 bits to 24 bits (5.2.3)
- Acquisition time corresponds to 100 propeller revolutions (5.2.6)
- Synchronous sampling requires channel phase difference <1° (5.2.4)
Implementation recommendations
Clause 4.2 recommends the use of hydrogen microbubble injection or guide edge roughening. Note:
| Definition of air content | α/αS (normal pressure) and (α/αS)TS (test pressure) must be clearly marked |
| Damping effect | The increase in bubble volume will cause the sound pressure to attenuate by 3-5dB |
Key points for real-scale prediction
Scale correction formula: ΔLs=20lg[(nsDs)/(nmDm)]+xlg(σs/σm)+ylg(ρs/ρm)+zlg(r)
Special note: When the model has no tip vortex cavitation but the real ship exists, an additional 3-8dB noise correction is required (Note to Clause 7.6)
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