CALCULATION OF GAS-DYNAMICS PARAMETERS AND STRESS-STRAIN STATE OF CELSIAN CERAMICS PRODUCTS

Abstract

In the work using the finite element method, an analysis of the behavior of nose fairings made of radio-transparent ceramic materials of celsian composition was carried out. Determination of parameters of gas dynamics and stress-strain state was carried out using licensed ANSYS software. SSG Reynold Stress turbulence model was chosen for accurate air flow simulation. Geometric and finite element models were used to calculate strength and temperature fields. The analysis of the results of gas-dynamic calculations shows that at the point of transition of the conical part of the rocket into the cylindrical part, there is a sharp change in the flow conditions and a disruption of the flow in the range of speeds of 100-1100 m/s. As a result of modeling the distribution of temperature fields with the stated task, it was established that the temperature on the inner surface of the fairing differs from the temperature on the outer surface by no more than ±1 °C on average, and the maximum surface heating temperature does not exceed 550 °C. According to the results of calculations of the stress-strain state under temperature regimes that simulate the conditions of their operation, it was concluded that under the considered conditions the equivalent (≤ 69.3 MPa) and main (≤ 40 MPa) stresses occurring in the nose fairing are not exceed the bending strength limit for celsian ceramics (290 MPa). It can be observed that the maximum temperature difference in thickness corresponds to the part of the fairing with the minimum radius. Movements on the surface of the fairing do not exceed 0.25 mm, which is acceptable according to the specified parameters. The parametric model provides advantages in justifying rational technical solutions. Ultimately, the nose fairing, made of celsian ceramics, will maintain its integrity in real operating conditions. Keywords: radiotransparent celsian ceramics; nose fairing; finite element method; gas dynamics; thermophysical calculations; strength; stress-strain state