A
safety design method for water tank used in airtightness test of aeroengine casing is disclosed. Based on the relevant technical parameters of the water tank and the
machine case with specific requirements, By using the
equations of motion and gas state, combining with dimensionless time and pressure and initial conditions, the
second order differential equations of dimensionless pressure and flight angle of plug fracture are established, the differential equations can be used to calculate different internal pressures, the initial and angular velocities of the plug fragment as it exits at the debris size, and then the
mechanics equation is established by using the fluid
mechanics principle, a method for calculating the
impact velocity of plug considering the resistance coefficient of medium is established, the theorem of
kinetic energy and the law of
conservation of energy are used to model and estimate the wall thickness of water tank, the
impact force of plug fragment and the
impact strength of fragment. In order to meet the needs of
engineering calculation, a conservative formula for calculating the initial velocity of plug separation is established. Finally, the safety designscheme of water tank for aero-engine casing airtightness test which meets the technical requirements can be obtained.