흡음형 소음기 스프리터 모델에 따른 동적 삽입손실 실험 연구

Abstract

This study is about silencers most commonly used as noise reduction measures for cogeneration facilities. Dynamic insertion loss (DIL) and pressure loss (pressure loss) were tested under various conditions that could actually occur depending on the on-site phase at the time of design. The purpose of this is to compare and consider experimental values and theoretical values and use them as basic data when designing soundproofing measures.

This paper consists of a total of six chapters, and the contents of each chapter are as follows. Chapter 1 introduction describes the research background and purpose, research contents, and methods. Chapter 2 In the theoretical background, the principle of silencer, the type and characteristics of silencer, and prior research were reviewed. Chapter 3 Silencer Design and Manufacture shows detailed drawings and processes manufactured by changing the opening rate, length, spritter thickness, and spritter shape of the silencer. In Chapter 4, noise, pressure in ducts, and duct wind speed were measured for each frequency band according to the silencer experimental conditions in the performance evaluation, and dynamic insertion loss (DIL) and pressure loss () were calculated. In Chapter 5, theoretical values and measured values were compared and considered. In Chapter 6, the research results were discussed and described as a conclusion. The contents of the conclusions summarized in Chapter 6 are as follows.

1) The dynamic insertion loss according to the change in the aperture ratio increased both the dynamic insertion loss and the pressure loss as the aperture ratio decreased.

2) Dynamic insertion loss due to length change increased dynamic insertion loss and pressure loss as the length increased.

3) As the sprinter thickness increased, there was no significant change in the dynamic insertion loss in the low frequency band of the center frequency 125 Hz to 250 Hz. However, at the center frequency of 500Hz or higher, the thinner the thickness, the better the dynamic insertion loss. In addition, the pressure loss also increased as the thickness of the sprinter was thinner.

4) Spritter shape changes were in the order of large dynamic insertion loss in the entire frequency band, followed by W, N, V, and straight. This increased dynamic insertion loss and pressure loss as the number of sprinters bent in all frequency ranges from 125 Hz to 4 K Hz at the center frequency.

5) The comparison between the calculated noise reduction value and the measured value confirmed that the measured value was larger than the theoretical value under most conditions of silencer length, aperture ratio, and sprayer thickness. If 50-70% of the measured value-theoretical value is used as a correction value for the theoretical value, it can be used for the design of silencer under other conditions. This study is about silencers most commonly used as noise reduction measures for cogeneration facilities. Dynamic insertion loss (DIL) and pressure loss (pressure loss) were tested under various conditions that could actually occur depending on the on-site phase at the time of design. The purpose of this is to compare and consider experimental values and theoretical values and use them as basic data when designing soundproofing measures.

This paper consists of a total of six chapters, and the contents of each chapter are as follows.

Chapter 1 (introduction) describes the background and purpose of the study, the contents and methods of the study. In Chapter 2 (theoretical background), the principle of silencer, the type and characteristics of silencer, and prior research were reviewed. Chapter 3 (Design and Manufacture of Silencer) shows detailed drawings and processes that are manufactured by changing the opening rate, length, spritter thickness, and spritter shape of the silencer. In Chapter 4 (Performance Evaluation), noise, pressure in ducts, and duct wind speed were measured for each frequency band according to the silencer experimental conditions, and dynamic insertion loss (DIL) and pressure loss () were calculated. In Chapter 5 (Comparison and Consideration of Theoretical Values and Measurements), theoretical values and measurements were compared and considered. In Chapter 6 (Conclusion), the research results were discussed and described. The contents of the conclusions summarized in Chapter 6 are as follows.

1) The dynamic insertion loss due to the change in the aperture ratio increased both 'dynamic insertion loss (DIL)' and 'pressure loss' as the aperture ratio decreased.

2) Dynamic insertion loss due to length change increased 'dynamic insertion loss (DIL)' and 'pressure loss' as the length increased.

3) There was no significant change in the 'dynamic insertion loss (DIL)' in the low frequency band with a center frequency of 125 Hz to 250 Hz as the spritter thickness increased. However, at the center frequency of 500Hz or higher, it was evaluated that the thinner the thickness, the better the 'dynamic insertion loss (DIL). In addition, the pressure loss also increased as the thickness of the sprinter was thinner.

4) As for the change in spritter shape, W, N, V, and straight type were in the order of "dynamic insertion loss (DIL)" in the entire frequency band. This means that the more the sprinter is bent in all frequency ranges from 125 Hz to 4 kHz, the higher the 'dynamic insertion loss (DIL)' and 'pressure loss'.

5) The comparison between the calculated noise reduction value and the measured value confirmed that the measured value was larger than the theoretical value under most conditions of silencer length, aperture ratio, and sprayer thickness. If 50-70% of the measured value-theoretical value is used as a correction value for the theoretical value, it can be used for the design of silencer under other conditions. (but not more than 10mmAq of pressure loss |본 연구는 열병합발전시설 소음저감대책으로 가장 일반적으로 사용하는 소음기의 동적삽입손실 및 압력손실 설계시 현장 상항에 따라 실제 발생할 수 있는 여러 설계 변수로 제작하여 압력손실 및 동적 삽입손실(DIL)을 실험을 통해 검토하였으며, 또한 실험값과 이론값을 비교 고찰하여 방음대책 설계시 기초자료로 활용함을 그 목적으로 한다.

본 논문은 총 6장으로 구성되어 있으며, 각 장의 내용은 다음과 같다.

제1장 서론에 연구배경 및 목적, 연구내용 및 방법을 기술하였다. 제2장 이론적 배경에서 소음기의 원리, 소음기의 종류 및 특성, 선행연구 고찰 등을 하였다. 제3장 소음기 설계 및 제작에서 소음기의 개구율, 길이, 스프리터 두께, 스프리터 형상을 변화시켜 제작하는 상세 도면 및 과정을 나타내었다. 제4장 성능평가에서 소음기 실험조건에 따라 주파수 대역별로 소음도와 덕트내 압력, 덕트풍속을 측정하였고, 이를 통해 동적삽입손실(DIL), 압력손실()을 산출하였다. 제5장 이론값과 측정값의 비교 및 고찰하였다. 제6장 결론에서 연구결과에 대한 논의를 하여 기술하였다. 제6장에서 정리한 결론의 내용은 다음과 같다.

1) 개구율 변화에 따른 동적 삽입손실은 개구율이 감소할수록 동적 동적 삽입손실과 압력손실 모두 증가하였다.

2) 길이 변화에 따른 동적 삽입손실은 길이가 길어질수록 동적 삽입손실과 압력손실이 증가하였다.

3) 스프리터 두께가 증가할수록 중심주파수 125Hz ~ 250Hz의 저주파수 대역에서 동적 삽입손실의 큰 변화는 없었다. 하지만 중심주파수 500Hz 이상에서는 두께가 얇을수록 동적삽입손실이 향상되는 것으로 평가되었다. 그리고 압력손실도 스프리터 두께가 얇을수록 증가하였다.

4) 스프리터 형상 변화는 주파수 전체 대역에서 동적 삽입손실이 큰 순서로 W, N, V, 일자형 순이였다. 이는 중심주파수 125Hz ~ 4K Hz까지 전 주파수 영역에서 스프리터의 꺽임이 많을수록 동적 삽입손실 및 압력손실이 증가하였다.

5) 소음 저감량 계산값과 측정값의 비교는 소음기 길이, 개구율, 스프리터 두께 대부분 조건에서 측정값이 이론값보다 큰 것을 확인 할 수 있었다. 측정값-이론값의 50~70%의 값을 이론값에 보정값으로 활용한다면 다른 조건의 소음기 설계에 활용할 수 있을 것으로 판단된다. (단, 압력손실 10mmAq이하 조건)