Effects of several analytical methods on calculated capsule running characteristics. Fundamental study on the unsteady running characteristics of pneumatic capsule (3rd report)

Theoretical analyses on capsule runnning were carried out by the method of characteristics under three different conditions; polytropic, irreversible adiabatic (based on the energy equation) and isentropic changes. The results of comparing the characteristics obtained by each method are summarized as follows: (1) Analytical results based on polytropic changes (n=1.01, 1.20) and irreversible adiabatic changes agree well with each other. Therefore, the former analysis is more useful because of its greater simplicity. (2) The results obtained under polytropic changes with n=1.40 are little different from those of the others for the pressure change in the pipe. (3) For the same convergence conditions, iterative calculation is necessary for analysis based on the irreversible adiabatic changes, but it is not necessary in other analyses. (4) Calculated results based on isentropic changes don't agree with the results obtained by the other methods or experimental results.