Airflow noise in duct should be controlled within the range of standard during duct design.

风道设计中要求风道的气流噪声必须控制在允许的范围内。

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Airflow noise in duct should be controlled within the range of standard during duct design.

风道设计中要求风道的气流噪声必须控制在允许的范围内。

youdao