Numerical and Experimental Investigation on Key Parameters of the Respimat® Spray Inhaler

Effect of airflow rate on droplet deposition of an impinging-jet inhaler in the human respiratory tract

This paper presents a numerical investigation to understand the transport and deposition of sprays emitted by an impinging-jet inhaler in the human respiratory tract under different inhalation flow rates. An injection model is used for the numerical simulations considering the spreading angles of the spray in the two directions, which are measured from experiments. The model parameter is adjusted to match the mean droplet size measured in the previous experiment. A time-varying sinusoidal inhalation flow rate is utilized as airflow conditions, which is closer to the actual situation when using an inhaler. The results demonstrate that the inhalation airflow rate significantly affects the spray's transport behavior and deposition results in the respiratory tract. Both excessively high and low inhalation flow rates lead to an increase in deposition in the mouth-throat. A moderate inhalation flow rate reduces throat deposition while maximizing lung deposition. Higher inhalation flow rates enable faster delivery of the droplets to the lungs, whereas lower inhalation flow rates achieve a more uniform deposition over time in the lungs. The amount of deposition in different parts of the lung lobes follows a fixed order. This study provides valuable insights for optimizing the inhalation flow rate conditions of the impinging-jet inhaler for clinical applications.

Analysis and Test of Clamp Conveying Type Residual Film Recycling and Film Impurity Separation Mechanism

Aiming at the problem of the difficult separation of film in the process of farmland residual film recovery, a clamping conveying residual film recovery device was designed and studied. The device was mainly composed of a clamp plate, clamp plate conveying chain, chain wheel drive shaft, and the residual film conveying chain and frame. Firstly, the structure and working principle of the device are introduced. The tensile properties of the residual film are investigated to determine the relationship between the average clamping force, the height of the clamp plate, the spacing of the clamp plate, and the rotational speed of the sprocket. Then, the mechanical properties of the residual film are discussed. The influence weight of each factor on the film impurity separation rate is summarized by single factor tests. The regression equation between the factors and film impurity separation rate is established. The results of the variance analysis of regression equation show that the film impurity separation rate was 93.70% at 1.08 m/s conveying speed of clamp plate, with 12 clamp plates, and 7 residual film conveyor chains. Taking the maximum value of the film impurity separation rate (η) as the objective using MATLAB, the optimal result was in good agreement with the regression equation. In addition, the field test results show that the film impurity separation rate was 92.35%. Compared with the theoretical analysis results, the relative error was 1.35%. The research results provide a theoretical reference for the design of related devices.