Sugawara M, Hirai A, Seo Y, Miyajima Y, Uchibori T
Heart Institute of Japan, Tokyo Women's Medical College, Japan.
Front Med Biol Eng. 1991;3(1):45-55.
The issuing flow rate of a jet, Q0, is given by Q0 = U0A, where U0 is the issuing velocity of the jet and A is the cross-sectional area of the orifice. However, measurement of A of a regurgitant jet in the cardiovascular system is difficult. On the assumption that the jet is 'free' and turbulent, the following relations apply between the diameter of the orifice D, the length of the core region of the jet L, the centerline velocity of the jet Uc(chi) at an arbitrary distance chi(greater than L) from the orifice, and U0:L = 6.8D and Uc(chi)/U0 = L/chi. From these equations we obtain Q0 = 0.017 (chi Uc(chi))2/U0. Pulsatile jets issuing into an aqueous glycerol bath through orifices with various diameters were studied. U0, chi and Uc(chi) were measured with a color Doppler system. There was a good linear correlation between the peak flow rates estimated from the above equation and those measured with a flowmeter irrespective of the diameter of orifices (y = 0.93 chi + 3.8, r = 0.95, SEE = 6.6 ml/s). Assuming that the flow rate waveform is similar to the issuing velocity waveform, we estimated the issuing volume per stroke by integrating the issuing velocity. There was a good linear correlation between the estimated issuing volume and the known stroke volume of the pump (y = 1.0 chi + 2.6, r = 0.92, SEE = 2.8 ml).
射流的射出流量Q0由Q0 = U0A给出，其中U0是射流的射出速度，A是孔口的横截面积。然而，测量心血管系统中反流射流的A是困难的。假设射流是“自由”且湍流的，则孔口直径D、射流核心区域长度L、射流在距孔口任意距离χ（大于L）处的中心线速度Uc(χ)与U0之间存在以下关系：L = 6.8D且Uc(χ)/U0 = L/χ。由这些方程我们可得Q0 = 0.017 (χUc(χ))2/U0。研究了通过不同直径孔口向含水甘油浴中射出的脉动射流。用彩色多普勒系统测量U0、χ和Uc(χ)。无论孔口直径如何，根据上述方程估算的峰值流量与用流量计测量的峰值流量之间存在良好的线性相关性（y = 0.93χ + 3.8，r = 0.95，标准误 = 6.6 ml/s）。假设流量波形与射出速度波形相似，我们通过对射出速度进行积分来估算每搏射出量。估算的射出量与泵的已知每搏量之间存在良好的线性相关性（y = 1.0χ + 2.6，r = 0.92，标准误 = 2.8 ml）。
