Urea-SCR시스템에 적용하기 위한 액막형 선회분사기의 분사압력변화에 따른 분무특성이 실험적으로 조사되었다. 실험에 사용된 노즐은 형상비 3.1을 갖는 단공 압력식 액막형 선회노즐이며, 노즐선단에 분사되는 유체에 선회류를 형성하기 위한 선회기가 설치되어 있다. 노즐의 분사량 조절은 PWM(pulse width modulation)기법에 의해 제어되었다. 분무의 발달과정은 2차원 PIV에 의해 가시화되었으며, 분무각 변화가 조사되었다. 분무액적의 속도 및 크기는 2차원 PDPA에 의해 상온 대기압 조건에서 측정되었다. 분무구조는 분사압력에 큰 영향을 받으며, SMD는 분사압력 증가에 따라 감소하며 선행연구자의 반실험적 결과와 유사한 경향을 보임을 알 수 있었다.
In this study, the spray characteristics of a pressure swirl atomizer classified into a liquid sheet-type swirl nozzle for Urea-SCR system were investigated experimentally with the variation of injection pressure. The length to diameter ratio ($l_o/d$) of the nozzle was 3.1, and the swirler was set inside the nozzle tip to give injecting fluid angular momentum. The injection duration of the nozzle was controlled by PWM (pulse width modulation) modes. The development processes of the spray were imaged by a 2-D PIV system, and the change of spray angle was measured. The atomization characteristics, including axial velocity and SMD, were measured using a 2-D PDA system with the injection pressures at room temperature and ambient pressure conditions. As the experimental results, the injection pressure had a significant impact on the spray structure showing a different shape around the spray leading edge, and the smaller SMD was observed with increasing injection pressures, which was similar to that of the previous work.
