抄録
An orifice plate is provided in the midst of a flow tube about 30cm long. A reciprocating piston device with the cylinder coaxial with the meter run is located at about 5 flow tube diameters upstream of the orifice meter. On the downstream side, it forms a discharge flow tube and is open to the atmosphere at the end. This simple equipment enables us to obtain a particular type of pulsating air flow through the orifice under specified conditions, so that we attempted to formulate mathematically the changes of the state of air in the flow tube in an operating condition.
In making formulation, it was found that the principle of conservation of energy furnishes a satisfactory basis for reasoning. The increasing rate of the total amount of energy income and expenditure in the air in each section of the flow tube separated by the orifice plate is equated with the increasing rate of the internal energy of the air in that section. A set of ordinary differential equations obtained as the result of formulation is numerically integrated on a personal computer. The instantaneous values of pressure calculated in the upstream section of the flow tube were found to be satisfactorily in agreement with those observed from the oscillogram.
