## 4 Working Characteristics of the Secretion Clearance Ventilation System with Double Lungs
### Influence of Dimensionless Compliance on Secretion Clearance Ventilation System with Double Lungs  
When the value of right lung dimensionless compliance (\(C_{r}\)*) is set to 0.3333, 0.5000, and 0.6000, the corresponding value for the left lung dimensionless compliance (\(C_{l}\)*) is 0.6667, 0.5000, and 0.4000. The influence of dimensionless compliance on dimensionless pressure (\(p\)*) and dimensionless air mass flow (\(q\)*) is shown in Figures 7 and 8. In the right lung, with an increase in \(C_{r}\)*, the dimensionless time for the respiratory cycle decreases, and the dimensionless time is lower as the dimensionless pressure of the right lung (\(p_{r}\)*) remains equal to the dimensionless IPAP (\(p_{ipap}\)*). However, for the left lung, the opposite holds. As \(C_{l}\)* increases, the dimensionless time of the respiratory cycle increases, and as dimensionless pressure of the left lung (\(p_{l}\)*) approaches \(p_{ipap}\)* the dimensionless time also becomes longer. With an increase in \(C_{l}\)*, the slope of the \(p_{l}\)* curve becomes more gradual. When \(C_{r}\)* \(>C_{l}\)*, \(p_{l}^{*}\) stayed longer in \(p_{ipap}\)* than \(p_{r}\)* and stayed in dimensionless EPAP (\(p_{epap}\)*) for less than \(p_{r}\)*. When \(C_{r}\)* \(<C_{l}\)*, the state is opposite. Figure 7 shows that for both lungs, with an increase of \(C\)* the peak value of the air mass (\(q\)*) also increases. The dimensionless time becomes longer as negative \(q\)* returns to 0. With the same condition for the two lungs, when \(C_{r}\)* \(>C_{l}\)*, the positive right lung dimensionless air mass flow (\(q_{r}\)*) is higher than the positive left lung dimensionless air mass flow (\(q_{l}\)*), and when \(C_{r}\)* \(<C_{l}\)*, the positive \(q_{r}\)* is less than the positive \(q_{l}\)*. The influence of \(C_{r}\)* on the dimensionless peak suction air flow of right lung (\(q_{rs}\)*), the dimensionless peak suction air flow of left lung (\(q_{ls}\)*) and the dimensionless suction duration (\(T_{sd}\)*) is shown in Figures 9 and 10. These graphs are demarcated by \(C_{r}\)* = \(C_{l}\)* = 0.5. In Figure 6, when \(C_{r}\)* \(<\) 0.5 (implying \(C_{r}\)* \(<C_{l}\)*), the dimensionless peak suction flow (\(q_{s}\)*) of both lungs is about 0.5. It is just a coincidence that the constant value of the left lung compliance is the saturation point of the pressure curve. As the value of IPAP of ventilator output parameter is set to 22 cmH\({}_{2}\)O, when the basic value of compliance is less than 10 mL/cmH\({}_{2}\)O, the maximum pressure in one lung is equal to IPAP 38, which is a rule about compliance and maximum pulmonary pressure. According to the definition equation of compliance, when the pressure reaches the maximum value and does not change, the maximum flow is saturated. Therefore, the dimensionless peak suction flow (\(q_{s}\)*) of both lungs is approximately equal to 0.5. In Figure 10, the curve first increases and then decreases. This is because the suction duration is dependent on the lung whose compliance is less. When \(C_{r}\)\(>\)\(C_{l}\), the suction duration is determined by the left lung. The basic value of the left lung compliance is maintained at 10 mL/cmH\({}_{2}\)O so the suction duration remains unchanged. However the time reference (\(T_{0}\)) increases with the increase of the dimensionless compliance of the right lung (\(C_{r}\)*), so the second part of the curve shows a decline. Figure 8: Influence of dimensionless compliance on dimensionless air mass flow of two lungs. Figure 7: Influence of dimensionless compliance on dimensionless pressure of two lungs. Figure 9: Influence of right lung dimensionless compliance on dimensionless peak suction flow. Influence of Dimensionless Air Resistance on Secretion Clearance Ventilation System with Double Lungs  
According to Equation (17), when the value of right lung dimensionless air resistance (\(R_{r}\)*) is set to 1.6667, 2.0000 and 2.3333, the value of left lung dimensionless air resistance (\(R_{l}\)*) is 2.50, 2.00 and 1.75.