Investigación de bajo ruido de válvula mariposa (segunda parte)

Vervovalve-previo:
 
K: válvula mariposa
D: comparando las características de vibración y ruido de las dos válvulas en las mismas condiciones hidráulicas, podemos confirmar la efectividad del diseño estructural de bajo ruido.
 
 

3. Prueba de características de vibración y ruido de la válvula mariposa
3.1 Sistemas de prueba y condiciones de trabajo
Las características hidráulicas y acústicas de las dos válvulas mariposa reguladoras se prueban en una plataforma de prueba de tubería de bajo ruido de fondo, como se muestra en la Figura 4.
La efectividad del diseño estructural de bajo ruido se verifica comparando las características de vibración y ruido de las dos válvulas bajo las mismas condiciones hidráulicas. Como la válvula mariposa reguladora generalmente no se usa en aberturas más bajas, el ángulo de prueba comienza desde el 35% abierto. Las condiciones de prueba se muestran en la Tabla 1. Instale un transmisor de presión diferencial en la entrada y salida de la válvula para probar la caída de presión generada por el flujo a través de la válvula. El punto de medición de la aceleración de vibración está dispuesto de acuerdo con el sistema de coordenadas absolutas. Los seis puntos de medición se encuentran en la entrada y salida de la brida, la parte media y la parte inferior del cuerpo de la válvula. Un sensor de aceleración se coloca en cada punto de medición en el eje x (dirección de la tubería), y (dirección horizontal) y z (dirección del tallo de la válvula), con un total de 18 sensores de aceleración de vibración. El hidrófono está instalado en la entrada y salida de la válvula para medir el ruido de flujo.
 
 
 
Prueba de válvula DN80 Figura 4
 
Tabla 1 Condiciones de prueba de válvula

 
 
3.2 Comparison of hydraulic characteristics of valves
The hydraulic characteristics of the two DN80 valves are illustrated in Figure 5. The results show that after low-noise optimization, the resistance characteristics of the two valves are almost the same for openings greater than 60%. Only for openings less than 50% does the resistance of the low-noise valve increase, but compared to the original valve, the increase is small. The hydraulic state of the original valve at 70% open and the low-noise control valve at 75% open are consistent, with both having a resistance coefficient of 10.
 
 
 
 
Figure 5 Resistance coefficient of two DN80 valves at different openings
 
 
3.3 Comparison of valve vibration characteristics before and after improved design
When the resistance coefficient of the two valves is 10, the total vibration acceleration levels in three directions in the 10Hz-10kHz frequency band are shown in Table 2. The test results show that the vibration acceleration of the low-noise control valve has been significantly reduced, with the root mean square vibration acceleration in the three directions reduced by 13 dB, 13 dB, and 10 dB, respectively. This shows that the low-noise optimization design, involving the installation of layered baffles, can reduce the vibration level of the valve body through reasonable rectification without significantly affecting the hydraulic characteristics or increasing the valve resistance.
 
 
Table 2 Valve body vibration acceleration of two DN80 valves with the same resistance coefficient

 
 
 
3.4 Comparison of flow noise characteristics before and after improved design
The inlet and outlet flow noise spectra of the two valves with a resistance coefficient of 10 are shown in Figure 6. The inlet and outlet flow noise of the two valves in the 10Hz-2kHz frequency band is shown in Table 3. The test results show that the design structure of the low-noise control valve has a significant noise reduction effect, reducing flow noise levels at the inlet and outlet by 8 dB and 9 dB, respectively.
 
 
 
Table 3 Vibration acceleration of the two valves of DN100 with the same resistance coefficient

 
 
Figure 6 Inlet and outlet flow noise spectrum of DN80 valves
 
 
Conclusion
The general flow rules of the flow field in the butterfly valve are explored by calculating the flow field. Based on this, the geometric form of the valve plate is optimized. The flow field characteristics before and after optimization are compared, and experimental tests are conducted. Analysis of calculation and test results leads to the following conclusions:
(1) Through the flow or pressure drop test results at different openings, the resistance coefficient of the valve was obtained using the partial resistance element formula. The butterfly valves before and after optimization can achieve the same resistance coefficient at different openings.
(2) Under the same hydraulic conditions, the vibration and noise levels of the butterfly valve have been significantly reduced after optimization. The vibration acceleration of the valve body has been reduced by 10 to 13 dB (10 Hz to 10 kHz), and the inlet and outlet flow noise has been reduced by 8 to 9 dB (10 Hz to 2 kHz). This result verifies the effectiveness of the layered guide comb structure in reducing vibration and noise.