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This paper aims to better understand the dynamic characteristics of an aerostatic slider caused by a gas film, and the impact of a gas film slip on the load capacity, stiffness and dynamic stiffness of the guideway is studied.

In theory, the Navier velocity slip model is introduced for fluid continuous flow equation to calculate the flow state in the micro-state; in experimental techniques, the stiffness experiment of the guideway by digital inductance meter is performed under different loadings, which are used to inspect the simulation results.

The maximum value of bearing stiffness in the condition of considering that the gas slip is larger than that of not considering the gas slip, and the gas film clearance of maximum bearing stiffness in the condition of considering the gas slip is less than that of not considering the gas slip. This is verified by the measurement of the stiffness of the guideway.

This paper mostly studies the influence of the gas slip effects on the performance of the aerostatic guideway, which will make a certain contribution to the guideway stability and the machining precision of the machine tool.

This paper aims to study the influence degree of three factors affecting the vibration amplitude of aerostatic spindle and optimizes each factor.

The vibration amplitude of the spindle is characterized according to internal structure and operating characteristics of aerostatic spindle. The radial and axial vibration models of aerostatic spindle were established by the spring-damper system. The influence degree of main influencing factors on the spindle vibration amplitude was investigated through correlation analysis.

The results indicate that the crucial factor is aerostatic spindle speed and experiments validated that increasing spindle speed can enhance spindle stability. The influence of three factors on radial vibration is greater than that on axial vibration. Finally, the values of optimal working parameters were obtained by genetic algorithm.

The method in this article can effectively predict aerostatic spindle vibration amplitude and perfect the stability of aerostatic spindle.

The purpose of this study is to reveal the influence law of pressure-equalizing grooves on aerostatic bearings and improve the static performance of bearings by optimizing the distribution form of grooves.

In view of two kinds of common restrictor distribution forms on the thrust surface, the linear and the rectangular, six kinds of pressure-equalizing groove schemes were proposed – the line-shape, the extended-shape, the S-shape, the oblong-shape, the X-shape and the reticular-shape. Based on the analysis of lubrication theory of the orifice-type aerostatic bearing, the numerical simulations of different bearings were carried out. The pressure distributions and static characteristic curves of different bearings were obtained.

The study reveals that the adoption of the pressure-equalizing grooves can substantially improve the load capacity and static stiffness of the bearing and make the bearing maintain a uniform stress, which enhances operating accuracy and life of the bearing. The superior function of the reticular-shape groove is highlighted.

The research results can effectively guide the optimization design of aerostatic bearings and provide a crucial technical reference for application of ultra-precision aerostatic supporting system.

The purpose of this paper is to study the influence of number of feeding holes on the performance of aerostatic bearings with spindle rotation. In traditional design of aerostatic bearings, the selection of hole numbers is dependent only on spindle size. However, when the hole numbers of air feeding are enough, the performance of the aerostatic bearing cannot be enhanced by increasing the hole numbers.

The Reynolds equation is utilized to model the air film within bearing clearance at constant temperature and the state equation of adiabatic process is for air feeding within bearing clearance. The finite difference method with relaxation algorithm is utilized to determine the pressure distributions from discretized and coupled equations of flow continuity. The eccentricity, spindle speed, and the number and arrangement of feeding holes are considered in the analyses to determine the load capacity, attitude angle, and flow rate for the comparisons between various designs of aerostatic bearings.

It is seen from the simulation results that the aerostatic bearing designed with a small number of feeding holes and without locating at bearing bottom is most suitable for the spindle operating at high speed, while the bearing designed with a large number of feeding holes is suitable for the spindle operating at low speed, and the load capacity is increased with the increasing number of feeding holes for low journal speed.

The paper proposes an extensive database as a critical requirement in the design for number and arrangement of feeding holes of aerostatic bearings for the spindle operating at low or high speed.

The main types of fluid film bearing, irrespective of lubricant, are those relying on surface motion to generate the fluid film pressure and hence load capacity (hydrodynamic lubrication—or aerodynamic for gases), and those relying on an external supply of pressurized lubricant (hydrostatic or aerostatic lubrication). A bearing employing a mixture of the two lubrication modes is said to be hybrid. A special case of self‐acting bearings is the squeeze film bearing in which fluid pressure is generated due to the normal motion of the bearing surfaces. Particular bearing geometries will not be discussed.

The purpose of this paper is to study the mechanical properties of aerostatic guideway taking the structural deformation into account, and further improve the calculation method of guideway.

A theoretical model of fluid-structure interaction for the numerical simulation was established and mechanical properties of the aerostatic guideway with porous restrictors were solved based on computational fluid dynamics. The deformation law of the guideway with different materials and gas-film thicknesses was revealed, and its static and dynamic characteristic curves were obtained.

The results indicate that ceramics as the material of guideways exhibit good applicability due to the small deformation, the quick dynamic response and the relatively light weight. The rational initial gas-film of guideway is recommended.

The present work can provide ideas for the design and optimization of aerostatic guideways.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0288

Deals with the development of aerostatic‐cum‐aerodynamic hybrid conical bearings, running at 70,000 r.p.m., suitable for supports of high speed spindles. Conical bearing bush is designed for two plane admission, with eight holes in each plane, with a semi cone angle of 108. In case of static response, the interactions between the major parameters, are projected on 3D response surface curve. The results give the magnitude of radial load to get the benefit of optimally minimum eccentricity ratio. Experimental results show close agreement with the theoretical work in regard to “no‐rotation” cases. The exponential relationship existing between eccentricity ratio, radial load and supply pressure is generalised. Rigidity for the bearings developed, as seen from the response surface, supports the observations of previous researchers. For the use of designers, vital operational parameters have been tabulated. Estimated and experimental values of these parameters compare reasonably.

This paper aims to combine the grooves with an annular air thrust bearing with multi-hole restrictors and discusses the influence of the groove parameters on the bearing performance.

Four models of aerostatic bearings with grooves of different geometries are established. The pressure distribution, load-carrying capacity (LCC), stiffness and flow characteristics of the flow field in the bearing clearances are obtained by computational fluid dynamics simulation.

The numerical and simulation results show that air bearing with grooved restrictors can slow down the pressure drop at the air inlet and increase the LCC and stiffness of the bearing. The gas flow in the aerostatic bearing is also studied, and the air vortex in the recess is analyzed.

This research optimizes the structure of the annular air thrust bearing, analyzes the gas vortex in the recess, improves the LCC and stiffness of the bearing and provides a reference for the bearing in the selection of groove parameters.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2023-0006/

The purpose of this paper is to study the load capacity of nanoparticles-laden gas film (NLGF) in thrust bearing.

SiO₂ nanoparticles were added into gas to form an NLGF. The nanoparticles volume fraction in the film was controlled by a vibrator. The film thickness and the film pressure were measured by a micro cantilever displacement sensor and a membrane pressure sensor, respectively. The total load that makes the film thickness keeping constant was quantified, and then, the film load capacity was obtained.

The investigation shows that nanoparticles can enlarge the film load capacity remarkably; even a little amount of nanoparticles (0.01 per cent) could lead to a sharp rise. With the increase of nanoparticles volume fraction, load capacity increases. However, the increment of load capacity decreases gradually. In addition, the film pressure variation proves the enhancement effect of nanoparticles on the film load capacity.

The paper is restricted to the findings based on NLGF, which is formed by dispersing SiO₂ nanoparticles in gas film as an additive. The experimental results are applicable within the range of nanoparticles volume fraction of 0.01-0.33 per cent.

The fact that nanoparticles could enlarge the gas film load capacity is verified by experiment for the first time. This study reveals the corresponding relation between nanoparticles volume fraction and the film load capacity.