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The buckling failure of the afterburner cylinder is a serious safety concern for aero-engines. To tackle this issue, the buckling simulation analysis of the afterburner cylinder was carried out by using finite element method (FEM) software to obtain the buckling mode and critical buckling loads. It was found that the afterburner cylinder was susceptible to buckling when subjected to differential pressure or the compressive force of the rear flange. Buckling would occur when the differential pressure reached 0.4 times the atmospheric pressure or when the axial compressive force on the rear flange reached 222.8 kN. Buckling was also found at the front of the cylinder under the auxiliary mount load. Additionally, under various loads on the rear flange, buckling occurred in the rear section, with the buckling mode being closely related to the load characteristics. Based on the simulation results and structural design requirements, two structural improvements were proposed, including the wall-thickening scheme and the grid reinforcement scheme. FEM simulation analysis results showed that both schemes would improve the rigidity and stability of the afterburner cylinder. For the 0.3 mm increase in the wall thickness scheme, the critical buckling load increased by 17.86% to 66.4%; for the grid reinforcement scheme, the critical buckling load increased by 169% to 619%. Therefore, the grid reinforcement scheme had a stronger anti-buckling ability and was deemed the optimal solution. The findings of this paper could provide technical support for the structural design of large-sized and thin-walled components of aero-engines.

Heat transfer management of the combustion chamber walls of rocket engines is key to predicting their life-cycle. This study used a test apparatus to measure heat transfer on the inner wall of a film-cooled combustion chamber. Experiments on a heat-sink GH2/GO2 combustion chamber with film cooling at the injector head were carried out to measure the distribution of wall heat flux and temperature under different chamber pressures and propellant mixture ratios. Averaged heat fluxes and transient values were obtained in the tests, which found a high correlation between transient heat flux and chamber pressure. A heat flux peak appeared in the near-injector region, and its distance from the injector head increased with chamber pressure. The thermal loads decreased obviously when the mixture ratio was increased from 5.0 to 7.0. The measurement data were used to interpolate two-dimensional contours of the wall’s thermal loads. The results will be useful for the thermal-structural analysis needed to provide detailed boundary conditions in the hot-gas-side walls of rocket combustion chambers.

It is well-known that the phenylboronic acid derivatives have chemical interactions with sugars. Hence, stable nanoparticles with core-shell structure were formed by the covalent complexation between boronic acid groups of poly(3-acrylamidophenylboronic acid) (pAPBA) and hydroxyl groups of poly(2-lactobionamidoethyl methacrylate) (pLAMA). The image taken by transmission electron microscopy (TEM) shows that the nanoparticles had a size of about 200 nm and were irregular spheres. The methyl thiazolyl tetrazolium (MTT) assay suggests that the nanoparticles were non-cytotoxic on the human colorectal carcinoma (Caco-2) cells. The confocal laser scanning microscope (CLSM) images show that the nanoparticles could internalize into Caco-2 cells. The insulin-loaded nanoparticles by intranasal administration led to a significant decrease in the plasma glucose levels and the histological assessment revealed that the nanoparticles would not develop lesions in the nasal epithelium. The nanoparticles are promising carriers for peptide and protein drugs in nasal delivery.