CAJ | 학술논문

矩形通道内脉动流，流量的正弦脉动会引起压力的脉动，在层流区压力与正弦规律吻合良好，而在紊流区、过渡区和跨区域的压力脉动与正弦规律偏差较大。为了能够较为精确地计算管内压降，对矩形通道内脉动流进行了试验研究。通过测量截面为40 mm×3 mm的矩形通道内不同周期、振幅、平均值的正弦脉动流体的流量、压差，对压差数据分别采用一阶、二阶傅里叶级数进行拟合，发现用二阶傅里叶级数拟合压差数据，能够很好地反映压差的变化规律，并发现雷诺数-摩阻系数曲线呈‘8’字形。通过对二阶傅里叶级数的压差拟合公式进行分析、推导、拟合，得到了瞬时及平均摩阻系数的计算公式，其计算值与实验值的误差较小。
구형통도내맥동류，류량적정현맥동회인기압력적맥동，재층류구압력여정현규률문합량호，이재문류구、과도구화과구역적압력맥동여정현규률편차교대。위료능구교위정학지계산관내압강，대구형통도내맥동류진행료시험연구。통과측량절면위40 mm×3 mm적구형통도내불동주기、진폭、평균치적정현맥동류체적류량、압차，대압차수거분별채용일계、이계부리협급수진행의합，발현용이계부리협급수의합압차수거，능구흔호지반영압차적변화규률，병발현뢰낙수-마조계수곡선정‘8’자형。통과대이계부리협급수적압차의합공식진행분석、추도、의합，득도료순시급평균마조계수적계산공식，기계산치여실험치적오차교소。
The pulsating flow in a rectangular channel and the flow rate sine fluctuation have large deviation, lead-ing to pressure drop fluctuation, and in the lamina region this fluctuation also fits the sine law well. However, while in turbulent region, transition region, and inter-regional region the pressure drop fluctuation will deviate the sine law considerably. In order to calculate the pressure drop more precisely, an experiment of pulsating flow in the rec-tangular channel was performed. Flow rate and pressure drop of different periods, amplitudes and average value of sine pulsating flow were measured in a 40 mm × 3 mm rectangular channel. First-order Fourier series and second-order Fourier series were used to fit the pressure drop data, respectively. The second-order Fourier series was found to express the pressure variation well, and the Reynolds-friction coefficient curve's shape looks like‘8’ . The func-tions to calculate the instantaneous and average coefficient of friction resistance were derived by analyzing and fitting with the pressure drop of second-order Fourier series. The relative errors between the experimental pressure drop da-ta and the calculated results are minor.