Sound absorption function of glass wool:
Glass wool has better sound absorption function to high frequency sound.The main factors affecting the sound absorption function of centrifugal glass wool are thickness, density and air resistance.Density is the component per cubic meter of data.Air drag is the ratio of air pressure to air velocity per unit thickness.Air flow resistance is an important factor affecting the sound absorption function of centrifugal glass wool zui.The flow resistance is too small, the elucidation data is scarce, the air oscillation simply passes through, the sound absorption function drops;The flow resistance is too large, and the data is dense.Regarding the centrifugal glass wool, the sound absorption function has flow resistance.
In practical engineering, it is difficult to measure air flow resistance, but it can be roughly estimated and controlled by thickness and bulk density.
1. With the addition of thickness, the sound absorption coefficient of medium and low frequency was significantly added, but the change of high frequency was not significant (high frequency absorption was always large).
2. The thickness remains unchanged, the bulk density is added, and the sound absorption coefficient of medium and low frequency is also added;However, when the bulk density is added to a certain degree, the data becomes dense, the flow resistance is greater than the flow resistance, and the sound absorption coefficient decreases instead.For centrifugal glass wool with a bulk density of 16Kg/m3 and a thickness of over 5cm, the sound absorption coefficient of 125Hz at low frequency is about 0.2, and that of medium and high frequency (>500Hz) is now close to 1.When the thickness continues to increase from 5cm, the sound absorption coefficient of the low frequency will gradually improve. When the thickness is more than 1m, the sound absorption coefficient of the low frequency 125Hz will also be close to 1.When the thickness remains unchanged and the bulk density increases, the low-frequency sound absorption coefficient of the centrifugal glass wool will also keep improving. When the bulk density is close to 110kg/m3, the sound absorption function reaches the large value of zui, and is close to 0.6-0.7 at 50mm thick and frequency 125Hz.When the bulk density exceeds 120kg/m3, the sound absorption function decreases instead, because the data become fine and dense, and the sound absorption function of medium and high frequency is greatly affected. When the bulk density exceeds 300kg/m3, the sound absorption function decreases a lot.The thickness of sound absorbing glass wool commonly used in architectural acoustics is 2.5cm, 5cm, 10cm, and its bulk density is 16, 24, 32, 48, 80, 96, and 112kg/m.Centrifugal glass wool with a thickness of 5cm and a weight of 12-48kg/m3 is generally used.
The sound absorption function of glass wool is also closely related to the installation conditions.When there is an air layer on the back of the glass wool board, the sound absorption effect of the glass wool board is similar to that of the glass wool board without air layer of the same thickness.In particular, there will be a greater improvement in the sound absorption function of medium and low frequency than that of the data actually pasted on the hard surface. The sound absorption coefficient will be added with the thickness of the air layer, but the effect will not be significant after it is added to a certain value.