A blower silencer can only silence the noise in the gas flow. It will not silence any noise being radiated by the casings or structure of the machine.
Each time a lobe on the rotor passes the open port of either the inlet, or outlet, of the machine, it will generate a pulse. The total number of times this happens in one second is known as the lobe passing frequency. For a machine with two internal rotors, each with 3 lobes on each rotor, with the rotational speed at 100 RPM, the lobe passing frequency will be 2 x 3 x 100 / 60 = 10Hz
Pressure drop will be between 1% and 3% of absolute line pressure.
They are called reactive because the design consists of a series of small tubes which connect large chambers, at the junction between each small tube and the chamber it is connecting to the noise is reflected back towards the source. It is this reflection of noise that results in the term "reactive".
No, fibrous packs inside roots blower silencers usually fail quite quickly.
Not usually, this type of silencer usually consists of a series of chambers. The inlet and outlet nozzles are connected to different chambers, so it is difficult to have them very near to each other.
Orientation is not important unless there is some liquid carry over from the machine to which they are connected.
