Cavitation Mechanism Research Articles

Cavitation mechanism of high-speed helical gears induced by vibration

Study of vibration-cavitation in helical gear transmissions is few at present. However, cavitation bubbles collapse does generate high-pressure shocks that can disrupt the smoothness of helical gear transmissions. For this reason, this paper combines the cavitation two-phase flow model with the dynamics model of helical gears. The helical gear finite element model is solved to obtain the vibration responses and the results are used as boundary rotational conditions for helical gear cavitation flow analysis. In addition, the proposed models are verified by comparing it with the corresponding experimental results. The obtained results demonstrate that cavitation is more severe at light load, high rotational speed and small helix angle, and the cavitation vapor distribution of helical gears is more uneven than those of spur gears.

Numerical investigation of partial cavitation in a Venturi tube by Eulerian-Lagrangian multiscale modelling

The cavitating flow in a Venturi tube has a complex flow structure. In this paper, the partial cavitation in an axisymmetric Venturi tube, dominated by bubbly shock, is investigated by utilizing Eulerian-Lagrangian multiscale modelling. The unsteady partial cavitation is simulated by Large Eddy Simulation coupled with the Volume of Fluid and the Discrete Bubble Model. The numerical results show a well agreement with the high-speed photography. Through a comprehensive analysis of the development and transportation of macro cavities and micro bubbles, a detailed explanation of the cavity shedding process triggered by bubbly shock is provided. The results highlight the precise capability of the multi-scale method in elucidating the intricate flow field induced by partial cavitation. The findings may pave the way for the further investigations on the underlying mechanisms of partial cavitation, fostering a deeper understanding of bubbly shock dominated cavitating flow.

Investigation of cavitation characteristics in an aircraft centrifugal fuel pump

Cavitation is a classic gas–liquid two-phase flow phenomenon that needs to be restricted for the hydraulic performance enhancement of centrifugal pumps. However, due to the particularity of fuel mediums and rigorous aviation conditions, the characteristics of cavitation occurring in aircraft centrifugal fuel pumps have not been elaborated. In this research, cavitation characteristics in an aircraft centrifugal fuel pump with a high rotational speed of 14,000 rpm were investigated by considering the influence of the flow rate ranging from 0.2Qd to 1.2Qd and the fuel temperature ranging from 20 °C to 100 °C. An experiment for testing the hydraulic performance of an aircraft centrifugal fuel pump was built, and a corresponding numerical simulation of gas–liquid two-phase flow was employed. The distributions of the pressure, streamlines, and turbulence kinetic energy in the centrifugal pump for different flow rates and fuel temperatures were comparatively analyzed. The net positive suction head available (NPSHa) was defined to represent the cavitation degree, and the net positive suction head required (NPSHr) was introduced to characterize the critical cavitation occurrence. It was also found that a large area of cavitation bubbles was generated in the inducer and that this area grew to block the flow channel of the impeller when the NPSHa was close to or lower than the NPSHr, which was the cavitation mechanism of hydraulic performance degradation. Additionally, the developments of the NPSHr with the flow rate and fuel temperature were determined adequately using natural exponential curve fitting. It was deduced that the occurrence of cavitation was more sensitive to higher flow rates, especially when the flow rate was higher than the designed flow rate. The effect of fuel temperature variations should also be considered for the long-time high-speed operation of centrifugal fuel pumps in the aerospace industry.

Energy dissipation mechanism of tip-leakage cavitation in mixed-flow pump blades

Tip leakage flow is one of the significant factors influencing the internal flow stability of mixed-flow pumps, and in severe cases, it can lead to channel blockage and energy loss. In order to gain a deeper understanding of the energy dissipation mechanism induced by tip leakage vortex cavitation, this study is based on the Wray–Agarwal (WA) turbulence model and the homogeneous flow model, investigating the cavitation flow characteristics of mixed-flow pumps. Additionally, the entropy production theory is employed to evaluate the energy losses within the mixed-flow pump and analyze the components of energy loss in the impeller and guide vanes. The research results reveal that with increasing cavitation intensity, the low-pressure region at the leading edge of the blade extends toward the trailing edge, influencing the static pressure distribution on the blade's pressure side. Leakage flow and the spatial distribution of leakage vortices move closer to the suction side of the blade with increasing cavitation intensity. Cavitation primarily affects the energy losses in the impeller region, with turbulent dissipation being the main source of energy loss. High turbulent dissipation zones are concentrated at the trailing edge of the blade, correlating with recirculation vortices and trailing-edge vortices. This study provides theoretical insights with practical implications for enhancing the cavitation performance of mixed-flow pumps, offering valuable guidance for design and operation.

A capillary-induced negative pressure is able to initiate heterogeneous cavitation.

A capillarity-induced negative pressure is of general importance for understanding the phase behaviors of liquids in small pores and cracks. A unique example is the embolism in the xylem of plants and the cavitation at the limiting negative pressure generated by evaporation of water from nanocapillaries in the cell walls of leaves. In this work, by combining the effect of a capillary and cavitation together, we demonstrate with molecular dynamics (MD) simulations that capillarity is able to induce spontaneous cavitation in the presence of hydrophobic heterogeneities. Our simulation results reveal separately how the capillary generates a negative pressure and how the generated negative pressure affects the onset of cavitation. We then interpret the cavitation mechanism and determine the occurrence of cavitation as a function of the hydrophobicity of the nucleating substrates where the cavitation initiates and as a function of the hydrophilicity of the capillary tube from which the negative pressure generates. Our results reveal that the capillary-induced cavitation can be described well with a heterogeneous nucleation mechanism, within the framework of classical nucleation theory.

Study of non-constant local cavitation suppression in micro-wedge structure

To alleviate the negative impacts of cavitation phenomenon on hydrodynamic machinery, such as mechanical vibration and noise, a hydrofoil model is established based on the micro-wedge structure, and numerical simulation of the hydrofoil is carried out by using the modified turbulence model k–omega shear stress transport (SST k–ω) to analyze the lift coefficient of drag, pressure pulsation, cavitation volume fraction, cavitation volume morphology, and turbulent kinetic energy distribution, and to reveal the inhibition of cavitation mechanism of the chord direction of the placement and the height of the micro-wedge structure coupling. The results show that the height of the micro-wedge structure determined by the thickness of the boundary layer is an important parameter affecting the cavitation performance, and the micro-wedge structure with a smaller height will produce better cavitation suppression, and the height of 0.05 mm has the best suppression effect, and the suppression of the main frequency of pulsation and the amplitude of pulsation shows a positive effect. The micro-wedge structure arranged on the hydrofoil can delay the change cycle of the cavitation volume to different degrees, in which the chordwise position of 3.5 mm has the best cavitation suppression effect, and the cavitation suppression rate is about 16.7%.

Development of an In Vitro Model to Study Mechanisms of Ultrasound-Targeted Microbubble Cavitation–Mediated Blood–Brain Barrier Opening

Ultrasound-targeted microbubble cavitation (UTMC)-mediated blood-brain barrier (BBB) opening is being explored as a method to increase drug delivery to the brain. This strategy has progressed to clinical trials for various neurological disorders, but the underlying cellular mechanisms are incompletely understood. In the study described here, a contact co-culture transwell model of the BBB was developed that can be used to determine the signaling cascade leading to increased BBB permeability. This BBB model consists of bEnd.3 cells and C8-D1A astrocytes seeded on opposite sides of a transwell membrane. Pulsed ultrasound (US) is applied to lipid microbubbles (MBs), and the change in barrier permeability is measured via transendothelial electrical resistance and dextran flux. Live cell calcium imaging (Fluo-4 AM) is performed during UTMC treatment. This model exhibits important features of the BBB, including endothelial tight junctions, and is more restrictive than the endothelial cell (EC) monolayer alone. When US is applied to MBs in contact with the ECs, BBB permeability increases in this model by two mechanisms: UTMC induces pore formation in the EC membrane (sonoporation), leading to increased transcellular permeability, and UTMC causes formation of reversible inter-endothelial gaps, which increases paracellular permeability. Additionally, this study determines that calcium influx into ECs mediates the increase in BBB permeability after UTMC in this model. Both transcellular and paracellular permeability can be used to increase drug delivery to the brain. Future studies can use this model to determine how UTMC-induced calcium-mediated signaling increases BBB permeability.

Fluid analysis of the cavitation of the microsegment gear pump operating at high-pressure condition

To investigate the cavitation of the microsegment gear pump and its effect on the performance of the gear pump, the gear equations of the microsegment gear for the pump were given, the cavitation mechanism was described, and the dynamic cavitation model was derived. The fluid analysis of the microsegment gear pump was carried out using the computational fluid dynamics software (Fluent), and the evolution of cavitation and its effect on the outlet flow characteristics were investigated. The results show that: the vortex occurred at the back edge of the microsegment gear pump suction chamber teeth and the top of the teeth, thus producing cavitation; the cavitation presented periodic formation-development-disappearance of the process; cavitation led to increased outlet flow fluctuations and pressure pulsations, and also led to a decrease in the average value of outlet flow and average value of outlet pressure. The periodic cavitation led to the periodic fluctuation in outlet flow and pressure. At the same time, cavitation also caused a decrease in the total head of the microsegment gear pump. Cavitation in the microsegment gear pump increased with increasing the speed and decreasing the suction pressure.

Effect of Shock-Wave-Mediated Collapse on Nanobubble Characteristics.

To enhance the comprehension of the cavitation mechanism and explore its practical use in industrial production, this study developed models involving oxygen, varying bubble radii, and bubble quantities. This study uses molecular dynamics simulations coupled with the momentum mirror method to examine the collapse characteristics of bubbles during ultrasonic cavitation. The investigation uncovers patterns in the fluctuation of the maximum local density of water molecules, released pressure, and temperature. The findings demonstrate that, when oxygen-containing bubbles collapse at identical radii, the local density is notably higher and diminishes more rapidly. Moreover, the changes in the shape exhibit greater regularity. During the bubble collapse, a depression forms on the bubble's surface, coinciding with a notable surge in local density around the depression. As bubble radii and quantities increase, so does the local density along with a concurrent rise in the maximum pressure. Intriguingly, the model demonstrates the lowest pressure at Z = 35 Å accompanied by the emergence of a small crescent-shaped region with a reduced density. Throughout the pressure ascension phase, the rate of the maximum pressure change escalates with an increase in the number of bubbles. Conversely, during the pressure descent phase, the rate of the maximum pressure change diminishes with a growing number of bubbles. However, it is important to note that the maximum pressure does not exhibit a direct correlation with the number of bubbles. Ultimately, this study provides valuable technical guidance and a theoretical foundation for the integration of ultrasonic cavitation in industrial production processes.

Cavitation cloud formation and surface damage of a model stone in a high-intensity focused ultrasound field

This work investigates the fundamental role of cavitation bubble clouds in stone comminution by focused ultrasound. The fragmentation of stones by ultrasound has applications in medical lithotripsy for the comminution of kidney stones or gall stones, where their fragmentation is believed to result from the high acoustic wave energy as well as the formation of cavitation. Cavitation is known to contribute to erosion and to cause damage away from the target, yet the exact contribution and mechanisms of cavitation remain currently unclear. Based on in situ experimental observations, post-exposure microtomography and acoustic simulations, the present work sheds light on the fundamental role of cavitation bubbles in the stone surface fragmentation by correlating the detected damage to the observed bubble activity. Our results show that not all clouds erode the stone, but only those located in preferential nucleation sites whose locations are herein examined. Furthermore, quantitative characterizations of the bubble clouds and their trajectories within the ultrasonic field are discussed. These include experiments with and without the presence of a model stone in the acoustic path length. Finally, the optimal stone-to-source distance maximizing the cavitation-induced surface damage area has been determined. Assuming the pressure magnitude within the focal region to exceed the cavitation pressure threshold, this location does not correspond to the acoustic focus, where the pressure is maximal, but rather to the region where the acoustic beam and thereby the acoustic cavitation activity near the stone surface is the widest.

Research Progress on Identification and Suppression Methods for Monitoring the Cavitation State of Centrifugal Pumps

Cavitation is a detrimental phenomenon in hydraulic machinery, adversely impacting its performance, inducing vibration and noise, and leading to corrosion damage of overflow components. Centrifugal pump internal cavitation will lead to severe vibration and noise, and not only will the performance of hydraulic machinery be adversely affected but the impact generated by the collapse of the vacuole will also cause damage to the impeller wall structure, seriously affecting the safety of the equipment’s operation. To prevent the generation and development of internal cavitation in centrifugal pumps, to prevent the hydraulic machinery from being in a state of cavitation for a long time, to avoid the failure of the unit, and to realize the predictive maintenance of centrifugal pumps, therefore, it is of great significance to research the methods for monitoring the cavitation of hydraulic machinery and the methods for suppressing the cavitation. This paper comprehensively describes the centrifugal pump cavitation mechanism and associated hazards. It also discusses the current state of centrifugal pump cavitation monitoring methods, including commonly used approaches such as the flow-head method, high-speed photography, pressure pulsation method, acoustic emission method, and vibration method. A comparative analysis of these methods is presented. Additionally, the paper explores signal characterization methods for centrifugal pump cavitation, including time-domain feature extraction, frequency-domain feature extraction, and time–frequency-domain feature extraction. The current research status is elaborated upon. Moreover, the paper presents methods to mitigate cavitation and prevent its occurrence. Finally, it summarizes the ongoing research on identifying and determining the cavitation state in centrifugal pumps and offers insights into future research directions.

Two-phase lubrication characteristics of journal bearing in refrigerant-oil system under high-pressure environment considering gaseous cavitation

The journal-bearing system is crucial for the reliability of refrigerant compressors that operate under high-ambient-pressure environments. The pressure changes rapidly, which hereby results in the variation in solubility of refrigerant in oil, and causes gaseous cavitation of the refrigerant-oil mixture in the bearing. However, the cavitation mechanism under high-pressure environments is not well understood, and its impact on lubrication characteristics has been rarely discussed. In this paper, a numerical model is developed to simultaneously solve the gaseous cavitation and two-phase lubrication problems. The first systematic comparison of lubrication characteristics for constant-eccentricity journal bearings, in such a special environment, between the classical Reynolds boundary and gaseous cavitation boundary is presented. Results indicate the load-carrying capacity is reduced by about 3% at a lower eccentricity of 0.3, but is greatly enhanced by about 21% at a higher eccentricity of 0.9 due to the gaseous cavitation. Meanwhile, the ‘reverse’ flow rate is found to reach -0.057 at the end side of the bearing owing to sub-ambient pressure up to -1 MPa at the eccentricity of 0.8. The cavitation-induced sub-ambient pressure should be addressed for the design of the bearing operating in such pressurized refrigerant environments as ambient gas might be sucked into the bearing.

Study of the Mechanism of Cavitation in Inner-Hole Rotating Cavitators

To investigate the mechanism of cavitation, a mathematical model of the cavitation region and an expression for the gas volume fraction in the inner hole of a rotating cavitator are developed. Then, based on the realizable k-ε turbulence model and the Schner & Sauer cavitation model, the flow field is simulated numerically. With the help of pressure and streamlined distribution contours, velocity contours, and gas phase contours, the three stages of the cavitation process are simulated by the cavitation evolution model. Finally, the rate of heat generation is used as the experimental characterization of cavitation, and the cavitation mechanism is confirmed by experiments involving rotation speed and pressure. The results indicate that the cavitation effect can be measured by the generation of cavitation heat and that the influence of the rotation speed on the cavitation effect is more significant than that of the inlet pressure.

Experiment investigation on cavitation bubble and mechanism of anti-cavitation performance in the bionic pressure relief valve

The anti-cavitation ability of the bionic pressure relief valve is investigated, the void fraction λ is employed to quantitatively analyze the gas-phase volume fraction experimentally. The results show that the void fraction is positively correlated with the gas volume fraction. The higher the void fraction, the higher the cavitation strength. Cavitation length and area with the bionic valve core are decreased significantly because of the non-smooth bionic surface. Compared with the traditional valve with a smooth surface, the maximum cavitation length of the bionic valve is reduced by 31.48%, and the maximum cavitation area is reduced by 22.75%. Furthermore, the cavitation inhibition efficiency is proposed to assess the cavitation suppression behavior of the bionic valve. The maximum cavitation inhibition efficiency varies from 63.25% to 72.66% when the flow velocity is in the extent of 42.13–52.66 L/min. Due to the non-smooth bionic surface, the flow field could be effectively perturbed to generate an anti-vortex, the cavitation suppression performance is significantly improved.

Effect mechanisms of leading-edge tubercle on blade cavitation control in a waterjet pump

The bio-inspired leading-edge tubercles (LET) are specifically designed and exploited to control the blade cavitation dynamics under the inlet guide vans (IGVs) wake impacts in a waterjet pump. The experiments, numerical simulation, and modal analysis are jointly carried out to elaborate on the effects mechanisms and cavitation oscillations of the LET pump. It is observed that the tubercle blade cavitation is stably confined in the troughs with a tubular-like pattern and the spanwise coherent development is broken. The tubercles drive the flow turbulent and then form low pressure in the troughs to give rise to cavities. Weak counter-rotating vortex pairs can be identified in the tubercle trough. The analysis of vortex transportation demonstrates that vortex stretching and dilatation would be induced by tubercle cavitation. The loading instabilities obtained by Dynamic Mode Decomposition (DMD) indicate that the dominant oscillations emerge around the tubercles in the blade middle part regarding heavy loading. Due to the large-scale cavities depression by the tubercles, the thrust extremes in some revolutions could be efficiently avoided. In comparison with smooth and tubercle pumps, the thrust energy regarding the tonal and broadband frequency for a single blade and impeller are closing, which need to be further studied to degrade excited force instabilities. This work fundamentally investigates the cavitation instabilities and mechanisms in a tubercle waterjet pump, which could provide a guide on pump design to stabilize cavitation oscillations under uncertain inflow perturbations.

Controlled mechanism of dynamic behavior of water-based ultrasonic cavitation in coal pore microstructure

Coal pores are sealed as a result of water lock effect, which in turn inhibits coalbed methane (CBM) from desorbing and diffusing. It seriously restricts the efficient development of CBM in the complex geological environment. Relieving pore water lock (RPWL) in coal reservoirs is a scientific problem that puzzles CBM development. Currently, the widely-interested technology of enhancing coalbed methane recovery (ECBM) can not effectively break through the pore water lock. Ultrasonic cavitation can generate shaped charge micro-jets, high temperature, and high pressure, which may be a potential strategy to realize RPWL in coal reservoirs. It has been maturely applied in numerous fields such as medicine, chemical industry, and manufacturing industry. Therefore, water-based ultrasonic cavitation-enhanced coalbed methane recovery (WUC-ECBM) was proposed in this study. This technology has enormous application potential for the efficient and green development of CBM. However, as the theoretical key to the successful application of WUC-ECBM, its RPWL mechanism is still blank. In this paper, X-ray nondestructive testing and fluid invasion methods were used to reconstruct the digital model of coal pore microstructure. Through ultrasonic cavitation numerical simulation, the dynamic behavior mechanism of water-based ultrasonic cavitation was studied in coal pore systems, revealing the microscopic RPWL mechanism of WUC-ECBM. Results show that low metamorphic coal has a larger and fuller pore system, which reflects a stronger topological advantage. Small pores and throats are the main locations of ultrasonic cavitation. This spatial feature is consistent with pore water locking phenomenon. During the formation of a cavitation bubble, ultrasonic energy instantly weakens the surface tension of the water film and activates RPWL. When the cavitation bubble collapses, the micro-jets, high temperature, and high pressure wreak mechanical damage and thermal shock to pore water, accelerating the RPWL process. Ultrasonic frequency affects the cavitation threshold. Increasing ultrasonic power will significantly boost cavitation intensity in pores, particularly in high metamorphic coal. The research results contribute to the green, efficient and intelligent development of CBM in the harsh geological environment, and provide theoretical guidance for WUC-ECBM.

Experimental Parameters Influencing the Cavitation Noise of an Oscillating NACA0015 Hydrofoil

The strong increase in anthropogenic underwater noise has caused a growing intention to design quieter ships given that ship propellers are one of the dominating noise sources along the worldwide shipping routes. This creates an imminent demand for deeper knowledge on the noise generation mechanisms of propeller cavitation. A cavitating, oscillating two-dimensional NACA0015 hydrofoil is analyzed with hydrophone and high-speed video recording as a simplified and manipulatable representative of a propeller blade in a ship’s wake field for the identification of major influencing parameters on the radiated noise. A pneumatic drive allows the application of asymmetrical temporal courses of the angle of attack, a novel amendment to the widely reported sinusoidal setups. Three different courses are tested with various cavitation numbers. The combination of a moderate angle increase and a rapid decrease is found to generate significantly higher pressure peaks compared to symmetrical angular courses. Considering that the rapid change of the angle of attack caused by the inhomogeneous wake field behind the hull is the core of the cavitation occurrence, the understanding of its influence may contribute to the design of quieter ships in the future while still allowing for the necessary high propeller efficiency.

Experimental and theoretical study on cavitation of concrete targets penetrated by hypervelocity long rod projectiles

The cavitation phenomenon can seriously decrease the strike performance of military weapons. As military terminal-ballistic activities have turned to hypervelocity attacks, the cavitation effect existing in the hypervelocity penetration deserves more attention. In terms of long-rod hypervelocity penetration into concretes, this study presents an analytical cavity model for the prediction of the cavity diameter based on the two-stage cavitation mechanism and the u-v relationship. The two-stage mechanism involving mushrooming and radial momentum expansion is used to describe the cavitation modes and the penetration parameters for the projectiles used in the analytical model are determined by numerical simulations empirically. Besides, the three modes including rigidity, deformation and erosion are introduced into the cavity model to elucidate the projectile state. Moreover, the hypervelocity impact experiments on the long rods into semi-infinite concrete targets at velocities of 2117 ∼ 3086 m/s are carried out to observe the cavitation effect of concrete targets and for further validating the model through comparing with the experimental cavity profiles, where the cavity profile is quantified with silica gel, and the cavity diameter is found to be more than five times the projectile diameter. The cavitation effect is observed significantly and quantified from the experiment results. The cavity model is compared with the experimental cavity profiles, showing that the model has good applicability.

In situ observation of melt pool evolution in ultrasonic vibration-assisted directed energy deposition

The presence of defects, such as pores, in materials processed using additive manufacturing represents a challenge during the manufacturing of many engineering components. Recently, ultrasonic vibration-assisted (UV-A) directed energy deposition (DED) has been shown to reduce porosity, promote grain refinement, and enhance mechanical performance in metal components. Whereas it is evident that the formation of such microstructural features is affected by the melt pool behavior, the specific mechanisms by which ultrasonic vibration (UV) influences the melt pool remain elusive. In the present investigation, UV was applied in situ to DED of 316L stainless steel single tracks and bulk parts. For the first time, high-speed video imaging and thermal imaging were implemented in situ to quantitatively correlate the application of UV to melt pool evolution in DED. Extensive imaging data were coupled with in-depth microstructural characterization to develop a statistically robust dataset describing the observed phenomena. Our findings show that UV increases the melt pool peak temperature and dimensions, while improving the wettability of injected particles with the melt pool surface and reducing particle residence time. Near the substrate, we observe that UV results in a 92% decrease in porosity, and a 54% decrease in dendritic arm spacing. The effect of UV on the melt pool is caused by the combined mechanisms of acoustic cavitation, ultrasound absorption, and acoustic streaming. Through in situ imaging we demonstrate quantitatively that these phenomena, acting simultaneously, effectively diminish with increasing build height and size due to acoustic attenuation, consequently decreasing the positive effect of implementing UV-A DED. Thus, this research provides valuable insight into the value of in situ imaging, as well as the effects of UV on DED melt pool dynamics, the stochastic interactions between the melt pool and incoming powder particles, and the limitations of build geometry on the UV-A DED technique.

Cylinder Liner Velocity Calculation under Dynamic Condition in the Pursuit of Liner Cavitation Investigation of an Internal Combustion Engine

<div>An analytical method for nonlinear three-dimensional (3D) multi-body flexible dynamic time-domain analysis for a single-cylinder internal combustion (IC) engine consisting of piston, connecting rod, crank pin, and liner is developed. This piston is modeled as a 3D piston that collides with the liner as in a real engine. The goal is to investigate the piston slap force and subsequent liner vibration. Liner vibrational velocity is directly responsible for pressure fluctuations in the coolant region resulting in bubble formation and subsequent collapse. If the bubble collapse is closer to the liner surface, cavitation erosion in the liner might occur. The mechanism of liner cavitation is briefly explained, which would take a full computational fluid dynamics (CFD) model to develop, which is out of scope for the present work. However, as a first step, the present method focused on a comprehensive and accurate estimation of the highest inward and outward liner velocities, which are directly related to the bubble formation and collapse, respectively. Sensitivity of liner velocity to different engine-operating conditions (warm and hot, with highest skirt temperatures of 178 and 130°C), piston pin bore offsets (thrust side, anti-thrust side directions in the amounts of 0.6 mm, and the nominal no offset case), and liner thicknesses are determined. Piston thermal growth is considered as part of the analysis resulting in interference condition between piston skirt and liner under the hot operating condition and low minimum clearance under the warm condition. Correlation of liner velocity contour plots with real engine liner cavitation erosion is presented. Analytical model showed a maximum liner inward velocity of 55 mm/s with no piston pin offset under nominal engine-operating configuration. A correlation has been found between location of this highest liner velocity and location of the actual cavitation erosion in the field.</div>