Ring Wear Research Articles

Leakage and Force Coefficients of a Grooved Wet (Bubbly Liquid) Seal for Multiphase Pumps and Comparisons With Prior Test Results for a Three Wave Seal

Abstract In the subsea oil and gas industry, multiphase pumps and wet gas compressors are engineered choices saving transportation and separation facility costs. In these machines, seals handling multiple phase components must be able to operate without affecting the system efficiency and its dynamic stability. This paper, extending prior work conducted with uniform clearance and wavy surface annular seals, presents measurements of leakage and dynamic force coefficients in a grooved seal whose dimensions are scaled from an impeller wear ring seal in a boiler feed pump. The 14-grooves seal has diameter D = 127 mm, length L = 0.34 D, and clearance c = 0.211 mm; each groove has shallow depth dg ∼2.6 c and length Lg ∼ 3.4% L. At a shaft speed of 3.5 krpm (surface speed = 23.3 m/s), a mixture of air in ISO VG 10 oil with inlet gas volume fraction (GVF) ranging from 0 (just oil) to 0.7 (mostly air) lubricates the seal. The pressure ratio (inlet/exit) is 2.9. The flow is laminar since the liquid is viscous and the pressure drop is low. The measured mixture mass flow decreases continuously with an increase in inlet GVF. The seal stiffnesses (direct K and cross coupled k), added mass (M), and direct damping (C) coefficients are constant when the supplied mixture is low in gas content, GVF ≤ 0.1. As the gas content increases, 0.2 ≤ GVF ≤ 0.5, the seal direct dynamic stiffness becomes nil with an increase in excitation frequency, whereas k and C reduce steadily with GVF. In general, for GVF ≤ 0.5, the direct damping is invariant with frequency; variations appearing for GVF = 0.7. Compared against a three wave annular seal, the grooved seal offers much lower force coefficients, in particular the viscous damping. Thus, for laminar flow operation (heavy oil) with a low pressure drop as in a wear ring seal, a three wave seal is recommended as it also offers a significant centering stiffness.

Strength and corrosion analysis in alloy steel and E-glass composite wear ring in automotive engine cooling water pump

Abstract An automobile produces enormous heat when the process of combustion of fuel takes place in the engine cylinder. The heat liberated is very high and needs to be controlled. An engine cooling water pumps controls the very high heat liberated by the automotive vehicle. The present investigation focuses on the wear ring in an engine cooling pump. Generally these wear rings are composed of alloy AISI 4304 stainless steel. The wear ring is subjected to very critical conditions such as high heat, high working pressures, electrochemical reactions etc. during its service life due to which it wear out progressively and needs to be replaced. The prime motive of the present investigation is to increase the working life of the wear ring for this GFRP composite wear ring is simulated in ANSYS 14 and is subjected to same working conditions. A comparative strength analysis of steel and GFRP wear ring has been carried out. The results shows that mechanical strength of GFRP wear ring is far superior to steel wear rings. The rate of general corrosion has also been investigated and compared for both GFRP and steel. The results obtained shows that the rate of general corrosion for steel is 32.88% whereas the rate of general corrosion for GFRP is 2.03%. The GFRP wear ring also behaves as inert to various electrolysis processes and therefore there is no galvanic corrosion in the GFRP wear rings.

IMPROVEMENT OF A DESIGN OF A BOREHOLE PLUNGER PUMP FOR PRODUCING A LIQUID WITH SUSPENDED PARTICLES INCREASED CONCENTRATION

When a large amount of solid impurities (sand) is contained in the produced formation fluid, the operation of production wells is complicated. Their presence leads to an increase in hydroabrasive wear of parts and components of a downhole sucker rod pump and causes its plunger pair to be wedged. In addition, this leads to cork formation, which requires cleaning and flushing. To prevent this phenomenon, various types of sand filters and structural changes of plunger pairs of the rod pump are used. The analysis of the operation of sucker rod pumps for oil production at the Tuymazaneft NGDU fields of Bashneft-Dobycha LLC revealed the following main reasons for the failure of the underground part of well sucker rod pump units: blockage of suction and discharge valves (52.2 %), jamming of the plunger in the pump cylinder (36.5 %), gaps in valves (4.8 %), disconnection of the plunger from the rod (1.8 %), breakage of the rod string (1.7%), lack of tightness in the support of the plugin pump (1.1 %). As a result, the average operating time of the pump is reduced to failure and the presence of sand in the formation fluid can be considered the main problem. Based on the analysis of field data on the operation of the plunger pump under complicated conditions (increased concentration of suspended particles in the produced fluid), it is proposed to change its design. Improvement affected the pump plunger and its filter. The proposed developments have a detailed description of their design and principle of operation. Detailed field tests of the developed devices are presented, showing the effectiveness of its use. As a result of the use of pumps with shortened plungers (and the previous modes of operation of the wells did not change), good results were achieved in reducing the load in the TPS and increasing the pump coefficient, and the durability of the elements of the plunger pairs of sucker rod pumps. After examining the plungers, slight wear of the eccentric rings to center the plunger was detected. For the purpose of further use of shortened plungers, only the replacement of all rings is necessary. There is no need for expensive repair of plungers. In addition, there was no seizure of the plunger in the cylinder. Sand filters were installed in 2018 at the well Nos. 1246, 1356, 1623 NGDU Krasnokholmskneft LLC Bashneft-Dobycha. Before the filter was lowered into the wells, samples were taken that established the presence of mechanical impurities in the product. The concentration of suspended particles exceeded the norm by several dozen times, which can lead to premature failure of the pump. In addition, sludge traps were located between the filter and the shank to increase efficiency. The use of new developments together allows to increase the efficiency of the use of a sucker rod pump in difficult operating conditions.

Chaotic vibration reduction of vertically suspended centrifugal pumps by the effect of the mechanical design parameter on hydraulic forces

The chaotic vibration generated by slender rotor–stator contact in vertically suspended centrifugal pumps shows itself in wear and fatigue failure of shafts, bearings, wear rings, seals and impellers. In common design methods of rotary equipment, for validating designed products, virtual representations in Computer Aided Design tools are imported to simulation tools (e.g. ANSYS software) on the last step of the design process. In this research, the ability of a non-linear finite element model is examined to support decision-making, synthesis and interaction of design choices during earlier stages of design process. So, the back wear ring diameter as the adjustable mechanical design parameter is used to reduce chaotic behavior of the pump rotor without any difficulty in manufacturing or problematic effect on the major hydraulic properties. The non-linear finite element model of the rotor is discretized into an appropriate number of Timoshenko beam elements. The major non-linear terms, the geometric stiffening effect, and the gyroscopic effect are considered. Rotor–stator contact, considering the rotor–stator clearance and the rotor–stator friction coefficient are taken into account. The full-order equations of motion are obtained using Lagrangian approach and the finite element method, and then are integrated into a computational plan. This study presents an allowable domain of the mechanical design parameter in which chaotic vibrations of the slender rotor can be reduced effectively. Furthermore, this research shows a basic method in which some design stages can be run in parallel rather than in series can be used to reduce redesigning and optimization times.

Experimental Investigation of Transient Characteristics of a Double Suction Centrifugal Pump System during Starting Period

The starting phase for pumps in water transportation pipelines is crucial and has significant transient characteristics which merit further study in order to evaluate the operational stability of the pumping system. This paper presents the results of a study in which the relative steady operating conditions and starting period of a large double-suction centrifugal pump were monitored in real time, including pressure fluctuations, shaft run-out and vibration at the bearing. The transient characteristics of a double-suction centrifugal pump under different operating conditions have been analyzed using fast Fourier transform (FFT) and continuous wavelet transform (CWT). Results indicate broadband frequency components within the spectrum of pressure fluctuations in the volute casing under all test conditions, and the central frequency of the broadband frequency gradually decreases as flow rate increases and approaches the blade frequency, which is the primary reason for an increase in blade-frequency amplitude. This may produce a vibration frequency that is similar to the natural frequency of a certain part of the double-suction centrifugal pump during the starting period, which causes the resonance phenomenon. The radial force is also large during the starting period, which causes eccentric wear of the seal ring at the impeller inlet.

Effect of grooved cylinder liner depths on the tribological performances of cylinder liner-piston ring

PurposeFrictions in cylinder liner-piston ring often cause an inevitable loss of energy loss in the diesel engine. This study aims at evaluating the effect of depths in the cylinder liner groove texture on friction, wear and sealing performances.Design/methodology/approachFive depths of groove texture cylinder liners (50, 100, 150, 200, 250 µm) were fabricated, and experiments were carried out using a special-purpose diesel engine tester. Comparative analyses of cylinder liner contact resistances, piston ring wear losses and surface appearances were conducted with respect to different surface textures and applied loads.FindingsUnder no-load conditions, the cylinder liner with a 100 deep thread groove can significantly improve sealing and optimize its lubrication performance. On the other hand, the sealing is highly correlated with the depth of groove and the load within the cylinder liner. Under loaded conditions, the thread groove has less effect on the sealing performance.Originality/valueThe findings can provide feasible basis for the tribological design and production of diesel engines.

Estimation of lubricity properties of nanolubricants

Abstract The lubricating performances liquid lubricants can be enhanced by homogeneously dispersing nanoparticles as an additive and it is estimated by mechanico- dynamical test. Four-ball wear test is a standard mechanico- dynamical test used to evaluate the lubricating performances of conventional liquid lubricants by determining the lubricity properties such as wear ring width rotating top ball, load wear index of stationary lower balls and their surface texture modifications. Lubricity is the fluid property that characterizes friction and wear phenomenon in boundary lubrication regime. In this study, a methodology for estimating the lubricity properties of nanolubricants is discussed.

Tribological Behavior of a Polyester Composite System under Severe Wear Conditions

This work aims on the study of the wear resistance of a commercial polyester composite system under severe wear conditions. It is an example of composite engineering material manufactured from synthetic fibers and thermosetting resins with appealing physical and mechanical properties that make it very interesting for products like sheets, rods, tubes, flange, washers and wear ring. In order to make it suitable for applications where damage by metal roll surfaces can occur, the study of the wear behavior under specific conditions is then necessary. At this aim, a detailed experimental campaign, including tribological tests and microgeometrical measurements, was carried out. In particular, the tribological behaviour was studied through the pin-on-disk tests conducted at 209 mm/s as peripheral speed under an applied load comprising in the range of 10 - 70 N. The tests were followed by microgeometrical measurements by using a confocal microscope in order to critically observe the wear tracks, evaluate their depth, width and then to calculate the final less of volume. The results proved that the wear mechanisms founded for the composite under investigation differ from those commonly associated to metals; the surface asperities of the fibres allow to hold the lubricant inside the surface and thus assist in the maintenance of a continuous film on the working surface involving in very low friction coefficient.

Effect of piston ring geometries on lubrication and friction in diesel engine

Lubrication and friction in piston rings are of a greater importance which has been receiving significant attention from tribologists for a long time. The main subsystems which contribute to friction include the ring-pack/liner, piston-skirt/liner, piston-pin/connecting-rod and connecting rod-crankshaft bearings. Piston rings are used in engines mainly to reduce leakage of gas in the combustion chamber and simultaneously provide a lubrication film in order to reduce friction during its motion. Wear between piston rings and liner is inevitable and therefore in order to reduce it, different types of ring geometries are being used which has its own advantages and disadvantages. Another major problem being faced during operation is that oil from the liner gets transported by pumping, reverse blow by, inertia and squeezing of oil due to ring dynamics into the combustion chamber. The present work focuses on to investigate different ring geometries and their effects on friction and lubrication oil consumption. It was found that Tangential force has an inverse relationship with Oil Film Thickness and Oil filling ratio. Top ring friction is high at Top dead centres due to boundary lubrication. Ring Barrel height has a direct relationship with asperity friction and an inverse relationship with Oil Film Thickness. Axial width is directly proportional to the wear of rings, which is due to the area exposed to back pressure on the rings exerted by gases from combustion chamber. Second ring closed gap has a direct relationship with Inter-ring pressure thus increasing reverse blowby. Rings with a Positive twist are found to be stable during operation. For this analysis, AVL Excite software is being used and results are validated with an experimental model.

Colour-ring wear and loss effects in citizen science mark-resighting studies

BackgroundRing wear and loss may have important consequences for mark-recapture studies that aim to estimate survival trends. Our study quantifies the rates of wear and loss from a long-running colour-ringing project of the Eurasian Oystercatcher (Haematopus ostralegus) in the Netherlands.MethodsOur analysis included 8909 colour-ringed oystercatchers with 118,071 resightings, predominantly ringed and observed by citizen scientists. We quantified how ring wear and loss may vary with ring colour and age, and how this may impact resighting probabilities. We then determined how ring loss may impact survival estimates and resighting probabilities of mark-recapture models by simulating four scenarios of how citizen scientists may resight and report birds with lost colour rings.ResultsAnnual rates of colour ring loss averaged 2.5% compared with 1% for ring wear, but lost rings also had a higher reporting probability (31.2%) than worn rings (10.3%). Lost rings may not directly impact survival estimates since 50% of oystercatchers with lost rings could still be uniquely identified. Ring wear and loss rapidly increased between 10 and 15 years after ringing. Rates of ring loss were comparable amongst ring colours, but the wear rate appeared higher for red and white rings compared to other colours. Rates of ring wear and loss varied significantly amongst different regions in our study, which were characterised as having different habitat features. Differential rates of ring wear may have important implications for studies conducted over large geographical scales or of multiple species.ConclusionsBased on simulations of ring loss in our population, estimates of apparent survival may be 0.3–1.2% lower whilst the impact of ring wear was deemed even lower. We developed a table of recommendations containing advice for ring fitting, data collection, study design, and mark-recapture analyses, so that future colour-ringing studies can benefit from our experiences in collecting and analysing data of ring wear and loss through citizen science.

Dry sliding wear behavior of infiltrated particulate reinforced Ni/TiC composites

Nickel-Titanium carbide composites are promising candidates for abrasive applications where high electrical and thermal conductivity and good wear resistance are needed. This paper describes the dry sliding wear behavior of a Ni/TiC composite material. The composite with 60 vol% reinforcement was prepared by a liquid infiltration technique, obtaining a continuous matrix material and homogeneous distribution of the reinforcement. The wear behavior of the composite with residual porosity of 1.4% and hardness 49 HRC was investigated under two-body abrasion conditions using a pin-on-ring device with a counterpart ring made of M2 hard steel. An increase in the wear rate was observed when increasing the applied load and the sliding distance, while decreasing at a higher sliding speed. The first part of the wear process is characterized by a tribochemical reaction mechanism by oxidation of the matrix.At higher speed the increase in temperature between the surfaces favors the formation of stable and adherent oxides of the type NiO and likely TiO2 that act as lubricants. Iron oxide is also likely to form due to wear of M2 ring, most likely Fe3O4. The characteristics of the worn surfaces at higher load and lower speed suggest a dominant mechanism of adhesion wear, showing a significant amount of material displaced plastically towards the margin of the wear track. The TiC particles exposed on the composite surface reduce the load to the matrix, decreasing the wear rate of the ductile material.

Comparison of changes in retentive force and wear pattern of two stud attachments for implant overdentures: An in vitro study

Context: Edentulous patients often complain about the instability of mandibular denture. To overcome that, implant-supported overdentures (IODs) have been applied as a good prosthetic option. Aims: The current study compared the changes in retentive force and patterns of surface wear of nylon rings of two stud attachments (ball and locator) upon cyclic loading. Subjects and Methods: Two implant analogs were fixed parallel to each other, 22 mm apart, in custom-made rectangular blocks for each attachment system. Ten nylon inserts of each attachment system were tested. Universal testing machine was used to measure the retentive force, and a low-value fatigue testing machine was used for cyclic loading of 2500 insertion–removal cycles. Surface changes of the components were evaluated by scanning electron microscope (SEM). Statistical Analysis Used: Paired Student's t-test was used to determine groups that were statistically significant. Results: The greatest retention loss rate, i.e., the difference between the initial retentive force and final retentive force was observed in the ball attachment (6.20 N) followed by locator attachment (3.70 N). The results were found to be statistically significant (d ≤ 0.001**). Upon SEM analysis, the nylon inserts of ball attachment revealed more surface wear compared to that of locator attachment. Conclusions: For greater retention and longer function, locator overdenture attachment should be preferred for implant overdentures over ball attachment.

A Fault Diagnosis Model for Rotating Machinery Using VWC and MSFLA‐SVM Based on Vibration Signal Analysis

Fault diagnosis of rotating machinery mainly includes fault feature extraction and fault classification. Vibration signal from the operation of machinery usually could help diagnosing the operational state of equipment. Different types of fault usually have different vibrational features, which are actually the basis of fault diagnosis. This paper proposes a novel fault diagnosis model, which extracts features by combining vibration severity, dyadic wavelet energy time‐spectrum, and coefficient power spectrum of the maximum wavelet energy level (VWC) at the feature extraction stage. At the stage of fault classification, we design a support vector machine (SVM) based on the modified shuffled frog‐leaping algorithm (MSFLA) for the accurate classifying machinery fault method. Specifically, we use the MSFLA method to optimize SVM parameters. MSFLA can avoid getting trapped into local optimum, speeding up convergence, and improving classification accuracy. Finally, we evaluate our model on real rotating machinery platform, which has four different states, i.e., normal state, eccentric axle fault (EAF), bearing pedestal fault (BPF), and sealing ring wear fault (SRWF). As demonstrated by the results, the VWC method is efficient in extracting vibration signal features of rotating machinery. Based on the extracted features, we further compare our classification method with other three fault classification methods, i.e., backpropagation neural network (BPNN), artificial chemical reaction optimization algorithm (ACROA‐SVM), and SFLA‐SVM. The experiment results show that MSFLA‐SVM achieves a much higher fault classification rate than BPNN, ACROA‐SVM, and SFLA‐SVM.

Impact of Design Parameters on the Performance of Centrifugal Pumps

Abstract The burden of production is in the difficulties of installation, maintenance, and operations. Centrifugal pumps contain two main parts: an impeller (rotor) that rotates at the motor speed and imparts centrifugal forces to the production fluid and diffuser (stator) which is the fixed part that guides the flow to the discharge. The shape of the impeller influences the performance of the pump. Thus, the area of significance to the pump design is the impeller geometric parameters to achieve pump performance. The consumption of energy by the pump is caused by the failure to choose the right pump size for the system, improper installation, and pump operation. Poor pump performance may affect the plant operation such as maintenance cost, downtime, loss of production, increase in operating cost. The loss of the hydraulic performance of the centrifugal pump is as a result of the detachment of the impeller neck rings on the impellers. A design modification to the casing wear rings or impeller neck rings is recommended to smooth the entry of water into the eye of the impeller by reducing the gap between the casing wear ring and the impeller neck ring. Various tests are performed on the Rand Water centrifugal pump installed at Zuikerbourch Rand Water Pumping Station. These tests show that design parameters such as the diameter of the impeller, blade angles, and number of blades, suction diameter and discharge diameter can have considerable influence on the performance of the centrifugal pumps. On this basis, the design of a suitable impeller is proposed. A model to predict the efficiency losses of these pumps is proposed.

Mixed Flow Reactor Experiments and Modeling of Sulfuric Acid Neutralization in Lube Oil for Large Two-Stroke Diesel Engines

Lubrication oil for marine diesel engines contains additives in the form of CaCO3-based reverse micelles, which can neutralize condensing H2SO4, and thereby limit uncontrolled corrosive wear of the piston rings and cylinder liner. In the present work, the neutralization mechanism was studied experimentally and through modeling. Using a mixed flow reactor (MFR), the rate of the acid–base reaction was measured as a function of relevant process parameters. In addition, the competition between CaCO3 reverse micelles and NaOH droplets for a reaction with H2SO4 droplets in a lube oil emulsion was explored in a batch reactor. For the residence times investigated, the results show that CaCO3 conversion is significantly reduced when reaching a critically low Ca/S ratio. Furthermore, a mathematical model for the neutralization of H2SO4 droplets by CaCO3 reverse micelles in lube oil under well-mixed conditions was developed. Both the experimental data and simulations support previous results, suggesting that the limiting step in the neutralization mechanism is adsorption of reverse micelles onto the much larger H2SO4 droplets. Using the video-microscopy experiments of Fu et al. [ Tribol. Lett. 2006, 22 (3), 221], it was possible to estimate kinetic parameters for the adsorption-controlled reaction. The model was used to predict conversion of H2SO4 in a lube oil film at the cylinder liner surface for conditions relevant for a full-scale application. Calculations indicated that H2SO4 may reach the liner surface regardless of how well-wetted the surface is.

Chaotic Characteristics Study on Cylinder Liner-Piston Ring’s Friction Signal

Cylinder linear-piston ring is the most important frication pairs in the internal combustion engine and the friction signal can reflect the characteristics of the whole tribological system. The wear test was carried out using UMT-3 tester and the friction signal was denoised via wavelet technology for the determination of chaotic characteristics by principal component, the largest Lyapunov exponent and the Kolmogorov entropy. The results indicated that chaos theory is applicable to the research of cylinder linear-piston ring wear system due to its chaotic characteristics, which is of great significance to the tribological design and the identification of the state of wear process.

Dynamic analysis of slender rotor of vertically suspended centrifugal pumps due to various hydraulic design factors

If a rotor is excited at one of its natural frequencies, a resonance occurs. The resonance can lead to large amplitude oscillations and subsequently failures. Field experience proves that the excessive vibration of the rotor of centrifugal pumps shows itself in wear and fatigue failure of shafts, bearings, wear rings, seals and impellers. So, modal analysis of a pump rotor is of great concern to researchers, international standard organizations and industries. In this research, dynamic behavior of a nonlinear finite element model of slender rotor of vertically suspended centrifugal pumps is studied. The dynamic model of the rotor is discretized into an appropriate number of three-dimensional Timoshenko beam elements. In addition to the main nonlinear terms and particularly the geometric stiffening effect, the gyroscopic effect has been also taken into account. The full-order equations of the motion, which are obtained by the Lagrangian approach and the finite element method, are integrated into a computational plan. The ability of the recent nonlinear dynamic model, which is intended to furnish a basic model for further development of a more comprehensive model, is examined to track the coupling between different types of vibrations. The comprehensive modal analysis of the rotor due to various hydraulic design factors is presented.

Experiment and analysis of the rock breaking characteristics of disc cutter ring with small edge angle in high abrasive grounds

At present, the constant cross section (CCS) disc cutter with flat edge is widely used in TBM tunnelling project. But the problem of serious wear and low rock breaking efficiency appeared when the CCS disc cutter was driven into the high abrasive stratum. The disc cutter with small edge angle is designed in order to enhance the service life of the disc cutter in this paper. The simulation of the two kinds of cutter rings rock breaking were done based on the theoretical analysis used the theoretical model of CSM. It is found that the small edge angle cutter ring has good penetration and its performance is better than that of the flat edge cutter ring in high abrasive strata. The small edge angle cutter ring structure suitable for soft rock formation. The flat edge cutter ring has better performance in hard rock formation condition and is superior to the small edge angle cutter ring structure. The simulation results are consistent with the theoretical analysis. In the end, two different disc cutters having small edge angle and flat edge cutter ring, respectively, are used in the field cutting experiments performed by the authors of this study. The experiment results indicate that the small edge angle cutter ring wear faster than the flat edge cutter ring in the early stage of tunnelling, but it has higher driving efficiency, at the same time, prone to the phenomenon of edge collapse. Along with the advancing distance was lengthened, the excavating performance of small edge angle cutter ring is better after the edge angle wear flattened, and the service life than that of flat edge cutter ring slightly longer. The research results can provide a theoretical basis for the geological adaptability design of disc cutter in high abrasive grounds.

A CASE STUDY ON WEAR IN SOME BASIC PARTS OF TRACTOR ENGINES

The aim of recent research work is to investigate a case study on wear in some basic parts concentrated on the piston with oil-sealing rings, suction and exhaust valves and its guides. Some parts of the engine have been taken; piston engine and its rings (pressure and oil rings). Which was changed after 10 years at a rate of 3 hours of daily operation. A test (setting wear rate and friction coefficient) was performed for both the metal of the anti-slip rings oil as well as the inner part of the engine cylinder. The results proved that the rate of ring wear is greater than the rate of wear of the cylinder as well as the experiments showed the importance of lubrication in the engine since the results in the case of the sample after lubrication showed less wear rate than the dry sample without lubrication. The axial adjustment test was performed on a suction valve as well as an exhaust valve in the guide of each valve to determine the effect of deterioration after 10 years. The results showed that the exhaust valve was bent with 1o 40’ and the suction valve at 2° 20'. American Mechanical Engineering allows one degree in the case of rotary columns and three degrees of inclination in fixed columns as in the case of the sample.

On the Leakage, Torque, and Dynamic Force Coefficients of Air in Oil (Wet) Annular Seal: A Computational Fluid Dynamics Analysis Anchored to Test Data

Subsea pumps and compressors must withstand multiphase flows whose gas volume fraction (GVF) or liquid volume fraction (LVF) varies over a wide range. Gas or liquid content as a dispersed phase in the primary stream affects the leakage, drag torque, and dynamic forced performance of secondary flow components, namely seals, thus affecting the process efficiency and mechanical reliability of pumping/compressing systems, in particular during transient events with sudden changes in gas (or liquid) content. This paper, complementing a parallel experimental program, presents a computational fluid dynamics (CFD) analysis to predict the leakage, drag power, and dynamic force coefficients of a smooth surface, uniform clearance annular seal supplied with air in oil mixture whose inlet GVF varies discretely from 0.0 to 0.9, i.e., from a pure liquid stream to a nearly all-gas content mixture. The test seal has uniform radial clearance Cr = 0.203 mm, diameter D = 127 mm, and length L = 0.36 D. The tests were conducted with an inlet pressure/exit pressure ratio equal to 2.5 and a rotor surface speed of 23.3 m/s (3.5 krpm), similar to conditions in a pump neck wear ring seal. The CFD two-phase flow model, first to be anchored to test data, uses an Euler–Euler formulation and delivers information on the precise evolution of the GVF and the gas and liquid streams' velocity fields. Recreating the test data, the CFD seal mass leakage and drag power decrease steadily as the GVF increases. A multiple-frequency shaft whirl orbit method aids in the calculation of seal reaction force components, and from which dynamic force coefficients, frequency-dependent, follow. For operation with a pure liquid, the CFD results and test data produce a constant cross-coupled stiffness, damping, and added mass coefficients, while also verifying predictive formulas typical of a laminar flow. The injection of air in the oil stream, small or large in gas volume, immediately produces force coefficients that are frequency-dependent; in particular the direct dynamic stiffness which hardens with excitation frequency. The effect is most remarkable for small GVFs, as low as 0.2. The seal test direct damping and cross-coupled dynamic stiffness continuously drop with an increase in GVF. CFD predictions, along with results from a bulk-flow model (BFM), reproduce the test force coefficients with great fidelity. Incidentally, early engineering practice points out to air injection as a remedy to cure persistent (self-excited) vibration problems in vertical pumps, submersible and large size hydraulic. Presently, the model predictions, supported by the test data, demonstrate that even a small content of gas in the liquid stream significantly raises the seal direct stiffness, thus displacing the system critical speed away to safety. The sound speed of a gas in liquid mixture is a small fraction of those speeds for either the pure oil or the gas, hence amplifying the fluid compressibility that produces the stiffness hardening. The CFD model and a dedicated test rig, predictions and test data complementing each other, enable engineered seals for extreme applications.