﻿ 船舶空调通风管路噪声经验预报方法
 舰船科学技术  2023, Vol. 45 Issue (23): 56-61    DOI: 10.3404/j.issn.1672-7649.2023.23.010 PDF

Prediction of ship HVAC noise based on empirical method
XU Fei
Shanghai Merchant Ship Design and Research Institute, Shanghai 201203, China
Abstract: HVAC noise as the main noise source for ship cabin has been attracting widespread attention. HVAC noise prediction is advanced according to the analysis and calculation in order of noise source, duct components and target cabin. Flow noise and sound attenuation in HVAC duct systems are calculated respectively according to empirical formula. Then, sound power levels in duct terminal are calculated according to subsequence of components. Finally, total sound pressure levels in target cabin are combined logarithmically with statistical room acoustics. The noise prediction for this method can be used in initial design stage without specific details and complicated modeling of the duct components. The typical HVAC noise pressure levels of a container vessel are computed, which validate the engineering practicability of this method.
Key words: HVAC     duct noise     empirical method     container vessel
0 引　言

1 基本原理

 图 1 管路噪声预报原理图 Fig. 1 Schematic diagram of HVAC noise prediction

1） 通过经验公式或者设备厂商得到噪声源设备产生的气动噪声声功率级Lw

2） 通过经验公式得到空调通风管路系统中，各元件再生噪声声功率级Lw和噪声衰减量∆Lw；按照各元件在管路中的顺序依次计算得到管路终端声功率级；

3） 最后在目标舱室，结合房间常数R将声功率级转化为接受点处的声压级，并和其他声源引起的声压级进行能量叠加得到房间内总声压级LpLpA

2 计算公式 2.1 噪声源强度计算

2.2 管路元件再生噪声和衰减量计算

2.2.1 直管

 ${L_w} = 7 + 50\lg \nu + 10\lg S + \Delta {L_{oct}} 。$ (1)

 $\Delta {L_{oct}} = - 2 - 26\lg \left( {1.14 + 0.02\frac{{{f_m}}}{v}} \right)，$ (2)

 $\Delta {L_w} = \beta \cdot l。$ (3)

2.2.2 弯头和分支

 ${L_w} = L_w^ * + 10\lg \Delta f + 30\lg {d_a} + 50\lg {v_a} + K。$ (4)

 ${L_w}^ * = 12 - 21.5{\left( {\lg {S_t}} \right)^{1.268}} + \left( {32 + 13\lg {S_t}} \right) \cdot \lg \left( {{v_h}/{v_a}} \right) ，$ (5)
 $K = 13.9 \cdot \left( {3.43 - \lg {S_t}} \right) \cdot \left( {0.15 - r/{d_a}} \right)。$ (6)

 $\Delta {L_w} = 10\lg \left( {{S_1}/\sum\limits_{i = 1}^n {{S_i}} } \right)。$ (7)

2.2.3 变径管

 ${L_w} = A + B\lg v - 3K。$ (8)

 $\Delta {L_w} = 10\lg \left( {\frac{{{{\left( {r + 1} \right)}^2}}}{{4r}}} \right)。$ (9)

2.2.4 消声器

 ${L_w} = 96.5\lg v - 20.4\lg \Delta {p_t} - 19.7 + \Delta {L_{oct}} + K 。$ (10)

 $\begin{split} \Delta {L_{oct}} =& 30.6 - 71.4\lg {S_t} + 64.7{\left( {\lg {S_t}} \right)^2} -\\ &26.7{\left( {\lg {S_t}} \right)^3} + 3.4{\left( {\lg {S_t}} \right)^4}，\end{split}$ (11)
 $K = 15.5\lg D - 16.2\lg v + 21.9。$ (12)

2.2.5 风口

 ${L_w} = 10 + 60\lg \nu + 10\lg \left( {\frac{{2\Delta {p_t}}}{{\rho \cdot {v^2}}}} \right) + 10\lg S + \Delta {L_{oct}} 。$ (13)

 $\Delta {L_w} = 10\lg \left( {1 + {{\left( {\frac{{kc}}{{{\text{π}} {f_m}d}}} \right)}^{1.88}}} \right)。$ (14)

2.2.6 阀门

 ${L_w} = 10 + 60\lg \left( v \right) + 22\lg \left( {\frac{{2\Delta {p_t}}}{{\rho \cdot {v^2}}} + 1} \right) + 10\lg \left( S \right) + \Delta {L_{oct}}，$ (15)
 ${L_w} = 10 + 60\lg \left( v \right) + 28\lg \left( {\frac{{2\Delta {p_t}}}{{\rho \cdot {v^2}}} + 1} \right) + 10\lg \left( S \right) + \Delta {L_{oct}}。$ (16)

 图 2 百叶阀各倍频带修正值 Fig. 2 Octave band adjustments for damper valve
2.3 管路元件叠加

 图 3 管路元件组合示意 Fig. 3 Combination diagram for duct components

 $L_{w - out}^1 = 10\lg \left( {{{10}^{\left( {L_{w - out}^0 - \Delta L_w^1} \right)/10}} + {{10}^{L_w^1/10}}} \right) 。$ (17)

 $L_{w - out}^i = 10\lg \left( {{{10}^{\left( {L_{w - out}^{i - 1} - \Delta L_w^i} \right)/10}} + {{10}^{L_w^i/10}}} \right)。$ (18)

2.4 目标位置声压级计算

 ${L_p} = {L_w} + 10\lg \left( {\frac{Q}{{4{\text{π}} {r^2}}} + \frac{4}{R}} \right) 。$ (19)

 图 4 风口位于房间中的位置 Fig. 4 Directivity factor Q of the opening location
 $R = \frac{{S\bar \alpha }}{{1 - \bar \alpha }} 。$ (20)

 $\bar \alpha = \frac{{\sum {S_i}{\alpha _i}}}{S} 。$ (21)

3 计算实例

 图 5 通风管路布置示意图 Fig. 5 Layout of HVAC duct

4 结　语

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