Reduction APU Noise by Use of Perforated Muffler

In this research is prepared the optimum design muffler code for maximum silence in perforated muffler to use in APU exhaust. According to far Annex 16 the power of sound (SPL) must be less than 90 dB on ground from aircraft. One of the sources of noise on ground is the exhaust noise of APU. The APU is used for product pressurize air for main engine start and air condition and for produce electric energy. So the muffler must be use in APU exhaust. In this paper was studied the method of calculation and effective parameters on transmission loss. After that, a code was produced for design muffler with respect to limitation of dimension and designer requirement. For verification of design code, the result of this code was compared with test result. By this code the muffler was designed for respective aircraft by attention to limitation of situation.