Search results

This paper aims to investigate the performance of a ferrofluid-based hydrodynamic journal bearing system.

This paper presents a new design of ferrofluid-based hydrodynamic journal bearing. An experimental set-up consisting of a magnetic shaft along with a brass bearing was modified and developed. A permanent magnet was used to make the selected shaft material magnetic. The load and speed were varied to conduct the analyses for different test conditions.

The paper provides information about a design of ferrofluid-based journal bearing and its improved performances. For moderate to higher loads at different shaft speeds, it was found that because of the magnetization effect, the maximum film pressure in case of a ferrofluid lubricant increased up to approximately 60 per cent, compared with that of the conventional lubricant-based journal bearing system. Besides, the temperature rise was found smaller for ferrofluid lubricants, thus making the system cooler while running.

This paper offers a new design of magnetic bearing system for the experimental analysis by utilizing a magnetic shaft with a non-magnetic bearing. The present ferrofluid-based bearing design is less complicated from manufacturing point of view.

The paper aims to improve upon the performance of a squeeze film formed by a magnetic fluid between longitudinally rough conical plates.

The objectives are achieved by mathematically modeling a magnetic fluid‐based squeeze film between longitudinally rough conical plates. The roughness of the bearing surface is modeled by a stochastic random variable with non‐zero mean, variance and skewness. The standard approach is to solve associated Reynold's equation which is stochastically averaged with respect to the random roughness parameter. The scope of this paper is the industrial applications with regard to enhanced performance of the bearing system.

The findings indicate that the performance of the bearing gets enhanced due to negatively skewed roughness. It is also noticed that the standard deviation increases the load carrying capacity which is unlike the case of transverse surface roughness. Further, this paper suggests that there exist considerable scopes for enhancing the performance of the longitudinally rough bearing system by choosing a suitable combination of the magnetization parameter and the semi‐vertical angle of the cone.

From the industry point of view, this investigation will be certainly useful for improving the performance of a magnetic fluid‐based squeeze film between longitudinally rough conical plates.

The paper presents the improved performance of a squeeze film formed by a magnetic fluid between longitudinally rough conical plates and thereby extending the life period of the bearing system.

The purpose of this paper is to study and analyse the behaviour of a magnetic fluid-based squeeze film between rotating transversely rough porous annular plates, taking the elastic deformation into consideration.

The stochastic film thickness characterizing the roughness is considered to be asymmetric with non-zero mean and variance and skewness while a magnetic fluid is taken as the lubricant. The associated stochastically averaged Reynolds-type equation is solved with appropriate boundary conditions to obtain the pressure distribution, which in turn is used to derive the expression for the load-carrying capacity.

It is observed that the roughness of the bearing surfaces affects the performance adversely, although the bearing registers an improved performance owing to the magnetic fluid lubricant. Also, it is seen that the deformation causes reduced load-carrying capacity. The bearing can support a load even in the absence of flow, unlike the case of conventional lubricants.

The originality of the paper lies in the fact that the negative effect of porosity, deformation and standard deviation can be minimized to some extent by the positive effect of the magnetic fluid lubricant in the case of negatively skewed roughness by suitably choosing the rotational inertia and aspect ratio. This effect becomes sharper when negative variance occurs.

The purpose of this paper is to study and analyze the effect of roughness and magnetic fluid lubricant on the performance of the squeeze film formed when the upper plate with a porous facing approaches an impermeable and flat lower plate by considering the rotation of the plates.

The roughness of the bearing surface is modeled by a stochastic random variable with non‐zero mean, variance and skewness. The associated Reynolds' equation is stochastically averaged with respect to the random roughness parameter. Results for bearing performance characteristics such as load‐carrying capacity and response time for various values of mean, standard deviation and measure of symmetry are numerically computed. The results are presented graphically as well as in tabular form.

It is observed that the bearing suffers owing to the transverse surface roughness. However, negatively skewed roughness may enhance the performance of the bearing system for suitable values of variance. It is also seen that rotation decreases the load‐carrying capacity but it has marginal influence in the presence of the magnetic fluid. Further, the performance of the bearing system registers a steady improvement with the increasing values of the magnetization parameter. In addition, the response time follows the trends of the load‐carrying capacity.

The originality of the paper lies in the fact that the roughness must be accounted for while designing the bearing system, even though a suitable rotation ratio parameter is chosen in the presence of a strong magnetic fluid. Of course, the best performance of the bearing system is registered in the case of negatively skewed roughness.