For an aerostatic bearing with a multi-hole integrated restrictor, which achieved superior precision lubrication-bearing performance, the fluctuations of the velocity and the pressure of the flow field were investigated. In this paper, the large-eddy simulation method was used to solve the three-dimensional Navier–Stokes equation in the calculation area of the gas film flow field at the orifice outlet of an aerostatic bearing, while the overrelaxation iteration method was used to solve the Reynolds equation in the remaining calculation areas. The influence factors of the flow field, such as the diameter of the orifice, the gas supply pressure and the gas film clearance, were derived and discussed. The results showed that the diameter of the orifice and the gas film clearance of aerostatic bearings with a multi-hole integrated restrictor strongly affected the film flow field near the outlet of the restrictor under a specified gas supply pressure. There was a critical ratio between the gas film clearance and the diameter of the orifice of aerostatic bearings with a multi-hole integrated restrictor, which may be an initial signal and an important parameter of the flow field transition from laminar flow to turbulent flow.

In order to further study the performance of aerostatic bearing, an aerostatic bearing with a multihole integrated restrictor was proposed in this paper. Based on the physical model of aerostatic bearings, the governing equation was established, deduced discretely, and solved numerically by the finite-difference method and flow balance principle in Cartesian coordinates. The bearing capacity and stiffness of aerostatic bearings have been analyzed, and the relevant experimental research has been carried out in this paper. The results showed that the number of orifices in the integrated restrictor had a significant effect on the bearing capacity, and the maximum bearing capacity of a nine-hole integrated throttling bearing was approximately 1.9 times greater than that of a single-hole bearing. The bearing stiffness was greatly affected by the diameter of the orifices, and the optimum bearing stiffness was determined. The corresponding gas film clearance also changed accordingly.

In order to further explore and study the influencing factors and regulars of the gas film flow field at the outlet of the orifice of the aerostatic bearing, the large eddy simulation method was used to calculate the N-S equation in the calculation area of the gas film flow field at the outlet of the orifice of the aerostatic bearing, and the overrelaxation iteration method was used to solve the Reynolds equation in the other calculation areas, which was proposed in this paper. Based on the physical model of the outlet of the orifice of the aerostatic bearing, the solution area of the gas film flow field of the aerostatic bearing was solved, and the calculation results were analyzed and discussed. The results showed that there was a sharp drop of the gas film pressure at the outlet of the orifice of the aerostatic bearing and the separation of the gas film pressure became inconsistent in the thickness direction of gas film clearance h. It was assumed that there was a critical ratio θ between the gas film clearance h and the orifice diameter d of the aerostatic bearing, and when the ratio of gas film clearance h to the orifice diameter d was greater than the critical ratio θ, various fluctuations of the gas film flow field began to appear, which may be the initial signal state of the gas film flow field of the aerostatic bearing starting to transition to turbulence. It provided a theoretical basis and guidance for further study of the transition lubrication mechanism between the laminar and the turbulent flow at the outlet of the orifice of the aerostatic bearing in this paper.

The design of friction materials with integrated friction reduction and wear resistance functions has been a research challenge for many researchers and scholars, based on this problem, this paper proposes a nickel-based hard-soft composite coating structure. With 20CrMo steel as the matrix material, Ni20 powder doped with reinforced phase WC as hard coating material, using laser melting technology to prepare nickel-based hard coating on the surface of 20CrMo. PTFE emulsion and MoS₂ as a soft coating are prepared on the hard coating, and the nickel-based hard-soft composite coating is formed. At 6N-0.3 m/s, the new interface structure obtains the optimum tribological performance, and compared to 20CrMo, the friction coefficient and wear amount are reduced by 83% and 93% respectively. The new friction interface can obtain stable and prominent tribological properties at wide load and low to high speed, which can provide the guidance on the structural design of friction reduction and wear resistance materials.

Improving the tribological performance of M50 steel under the conditions of wide load range is of great significance. In this study, the interfacial structure of surface micropores filled with Sn–Ag–Cu or Sn–Ag–Cu/whisker carbon nanotubes (whiskerCNT) of M50 material was prepared by laser additive manufacturing and high-temperature infiltration. From 2 to 22 N, the lubrication characteristics of Sn–Ag–Cu and whiskerCNT in surface micropores of M50 was investigated. Results indicate that Sn–Ag–Cu can precipitate to the worn surface and form a lubricating layer, which has a good lubricating effect. Moreover, the flow behavior of Sn–Ag–Cu on a worn surface can play the role of crack healing. At higher load, the strength of the lubricating film is enhanced by whiskerCNT, which renders the lubricating film not vulnerable to premature rupture.

The regenerator plays an extremely important role in the Stirling circulation. A grid regenerator can be used for inverse Stirling machines at room temperature due to its low flow resistance. This paper proposes a hexagonal grid regenerator to theoretically explore heat transfer properties in the inverse Stirling cycle and establishes an approximate analytical model to analyze the effect mechanism of working frequency, thermal diffusivity and wall thickness on the oscillation flow. The results show that the wall thickness is one of the key factors affecting the equivalent heat transfer coefficient. Specifically, too small or too large wall thickness increases the instability of the heat transfer process. The ultimate wall thickness is determined by the equivalent heat transfer coefficient and thermal penetration depth, whose optimal value ensures not only sufficient heat exchange but also the full utilization of materials. With the increase in frequency, heat exchange performance is improved monotonously. Therefore, high–frequency operation can improve the heat exchange performance of the regenerator. In addition, an optimization criterion for the size of regenerator with the specific capacity of heat transfer as the objective parameter is proposed based on the equivalent heat transfer coefficient. The optimal parameters were obtained when relative thickness was set as 0.8 mm and the equivalent heat transfer coefficient was up to 10⁴–10⁵ W/m²·K indicating that the grid regenerator has broad application prospects in the inverse Stirling cycle.