API 521-2014 安全阀泄放噪声计算 Noise Level Calculation



According to 依据：API 521-2014		Noise Level Calculation 噪声计算
	Name 名称	单位	Source 公式/来源	Value 值
1	Data Input 输入
2	Mass flow through valve, qm 额定泄放量	kg/s		27
3	Inlet pressure, P1 泄放状态入口压力	MPa(A)		1.7
4	Gas temperature, t 泄放温度	℃		150
5	Outlet pressure, P2 安全阀背压	MPa(A)		0.1
6	Relative molecular mass, M 气体相对摩尔质量	g/mol		29
7	Ratio of the specific heats, k 气体绝热指数	/		1.41
8	Height of the vent aboveground, h 泄放点距地面高度	m		15
9	Distance from sound source, r 距泄放点任意距离r处	m		40
10	Params 过程
11	Gas temperature, T 泄放温度	K	T=t+273.15	423.15
12	Speed of sound in the gas, c 泄放状态介质声速	m/s		413.6686112
13	Relieving outlet pressure, Po 泄放状态出口压力	MPa(A)		0.895225598
14	Pressure ratio, PR 泄放状态压力比	/	PR=P1/Po	1.89896268
15	Base Noise level, L 基础噪声强度	dB	Figure 18	37.67050014
16	Result 结果
17	Noise level at distance 30 m, L30 距排放点30米处噪声强度	dB		104.3068892
18	Noise level at distance r, Lp 距排放点r米处噪声强度	dB		101.8081145
	Note: The above calculations are based on spherical spreading of the sound. If distances much larger than the height of the vent aboveground are of concern, add 3 dB to the calculated result to correct for hemispherical diffusion. 注：以上计算以声音作球面传播为依据，如果传播距离远大于放空点在地面以上的高度(10m为限)，计算结果应加上3dB作为修正。