Groove Depth Research Articles

Cadaveric study on the arterial blood supply to the middle third nasal skin: implications for aesthetic and reconstructive surgery.

To provide a detailed examination of the arterial blood supply to the middle third of the nasal skin through cadaveric dissections, identifying the primary arterial sources and their precise locations. Cadaveric dissections were performed on 14 hemifaces from fresh specimens. The main feeding arteries and their branches were carefully dissected under magnification. Morphometric characteristics of the specimens, along with the caliber of the arteries and their branches vascularizing the mid-third nasal skin were recorded, and statistically analyzed. Four main arteries were identified as responsible for the blood supply to the mid-third of the nasal skin: the facial artery, the nasal branch of the infra-orbital artery (nbIOA), the dorsal nasal artery, and the upper branches of the columellar plexus. The lateral nasal artery (LNA) and the nbIOA were the main contributors, each providing significantly larger arterial branches than the other sources (1.8 ± 0.8 branches of 0.67 ± 0.2mm for the LNA, p-value < 0.001-1 ± 0 branches of 0.55 ± 0.17mm for the nbIOA, p-value < 0.01). The largest arterial branch consistently penetrated the lateral and inferior angle of the mid-third nasal skin, originated either from the LNA or nbIOA. The LNA and nbIOA endorse crucial roles in the arterial blood supply to the mid-third nasal skin. Despite the variability in vascular anatomy, a consistent pattern of arterial supply with convergence in the depth of the alarfacial groove was observed. Understanding these patterns is vital for improving surgical precision and reducing the risk of complications in both aesthetic and reconstructive surgeries.

Thermal management performance of a novel elliptically grooved flat heat pipe system embedded with internally cooled condenser

Flat heat pipes (FHPs) with rectangular groove wick structures fail to sufficiently uplift the working fluid’s liquid meniscus to cover the upper sides of the groove walls due to the vertically flat wall design. This results in the formation of non-evaporative zones, particularly in the evaporator region, leading to elevated wall temperatures at high heat loads. To address this issue, a novel FHP with elliptical grooves as wick is designed and tested across heat loads ranging from 30 to 360 W. Elliptical groove depths of 0.5 mm and 0.7 mm are evaluated and compared to FHPs with rectangular grooves. Results showed that at 360 W, the 0.7 mm depth elliptical grooves resulted in 6.5 % reduction in evaporator wall temperature and 27.8 % reduction in thermal resistance, along with 31.5 % enhancement in effective thermal conductivity compared to rectangular grooves. The curvature of the elliptical grooves, combined with enhanced surface tension effects of the working fluid, efficiently uplifted the liquid meniscus to cover the upper wall of the groove, minimizing non-evaporative zones. Additionally, FHPs with elliptical grooves demonstrated lower entropy generation, indicating higher thermal efficiency. Consequently, FHPs with elliptical groove designs are concluded to be an efficient and suitable solution for the thermal management of miniaturized electronic devices.

The Preparation of MoS2/Metal Nanocomposites Functionalized with N-Oleoylethanolamine: Application as Lubricant Additives

In this study, MoS2 nanosheets have been prepared and treated ultrasonically with silver ammonia solutions. The MoS2/Ag precursor was reduced using dopamine (DA) as reducing and linking agent at room temperature, and it was subjected to a hydrothermal treatment to produce MoS2/Ag nanocomposites (denoted as MoAg). The MoAg samples were functionalized with N-oleoylethanolamine to improve dispersion in the base oil component of additives. Use of the functionalized MoAg (denoted as Fc-MoAg) as a lubricant additive for steel balls resulted in effective friction reduction and anti-wear. This work avoids ion exchange during exfoliation, and the Ag+ has been reduced to nano-silver particles by dopamine to enlarge the layer spaces of MoS2. Taking the case of lubrication with base oil containing Fc-Mo0.6Ag15, the wear scar diameters and coefficients of friction of the steel balls were 0.428 and 0.098 mm, respectively, which were about three-fifths base oil. In addition, MoS2/Cu and MoS2/Ni nanocomposites were synthesized and the tribological properties associated with steel/steel balls assessed. The results demonstrate that all MoS2/metal composites exhibit enhanced tribological behavior in the steel/steel pair tests. Both nanocomposite synergy and the tribofilm containing sulfide, oxide, carbide, and other compounds play important roles in achieving reduced friction and improved anti-wear. The friction and wear properties of base oil containing Fc-MoAg and commercial additives were evaluated using a four-ball wear tester with steel/steel, steel/zirconia and zirconia/zirconia pairs. The base oil containing Fc-MoAg delivered smaller coefficients of friction (COFs) and/or scarring groove depths than those observed with the use of pure base oil and base oil containing commercial additives.

The morphometry of distal tibia and posterior malleolus and its clinical implications in total ankle prosthesis.

The aim of this study is to reveal the morphometry of the distal tibia and posterior malleolus and to generate morphometric reference data for the tibial component of total ankle prosthesis. This study was performed on 121 human dry tibiae (47 right, 74 left). The morphometric measurements of distal tibial structures, tibial length and the distance between the medial and posterior malleolus were measured in this study. Measurements on 44 tibiae were repeated three times and averaged for minimizing intra-observer error. The tibial length was found 34.19 ± 2.31cm. Mean values of width of fibular notch at tibial plafond and 10mm proximal to the tibial plafond were 25.71 ± 2.44mm and 17.81 ± 2.46mm, respectively. Mean depth of fibular notch at tibial plafond and 10mm proximal to the tibial plafond were 3.60 ± 1.04mm and 3.37 ± 1.24mm, respectively. Mean height of fibular notch was found 48.21 ± 10.51mm. Mean width and height of medial malleolus were 25.08 ± 2.13mm and 14.73 ± 1.85mm, respectively. Mean width and length of tibial plafond were 27.71 ± 2.74mm and 26.96 ± 2.62mm, respectively. Mean values of width and height of posterior malleolus were measured 21.41 ± 3.26mm and 6.74 ± 1.56mm, respectively. Mean distance between medial and posterior malleolus was found 37.17 ± 3.53mm. Mean width and depth of malleolar groove were 10.26 ± 1.84mm and 1.73 ± 0.75mm, respectively. The mean intra-class correlation values were found between the 0.959 and 0.999. Knowing the distal tibial morphometry is crucial for designing convenient ankle replacement implants for Turkish population. To our knowledge, this study is the first in the literature that identifies posterior malleolar morphometry on dry tibiae. We believe that this study will make a significant contribution to the literature about distal tibial morphometry and especially the posterior malleolus and the data of our study can be used for designing total ankle prosthesis in Turkish population.

Sealing rubber ring design based on machine learning algorithm combined progressive optimization method

In this study, a progressive optimization method combining machine learning and optimization method is proposed and applied to seal structure design. The method is divided into two stages to select the optimal design gradually. So as to find the best design scheme meeting the design requirements. For optimal design, numerical calculation method is commonly used, but hard to evaluate the optimal solution. In this work, a series of numerical model considering the effect of super elastic material about O-ring study the waterproof performance behavior of a rubber seal. K nearest neighbors (KNN) of machine learning algorithms applied to the simulation data to predict the appropriate bolt pretension classification. Furthermore, use TOPSIS method to optimize the groove depth of 30 N bolt pretension classification. By using the TOPSIS method to consider the stress of the rubber component, optimization analysis is conducted to find the optimal design. Results show that the dual optimization method can quickly predict the best design scheme. Through the experiment, a prototype test under the condition of IPX7 verify the method. The design scheme selected by this method meets the waterproof grade requirements. There are no water stains on the surface of the O-ring and inside the motor. This paper provides a fast optimization design method for the design of sealing structure.

Bond strength prediction of externally bonded reinforcement on groove method (EBROG) using MARS-POA

The Externally Bonded Reinforcement on Grooves (EBROG) method represents an advancement in externally bonded reinforcement (EBR) techniques, specifically addressing the challenge of premature debonding often encountered in conventional Fiber Reinforced Polymer (FRP) applications directly bonded to concrete. This article introduces a novel and straightforward mathematical equation for predicting bond strength in the EBROG method using soft computing techniques for the first time. The study delves into the combined potential of the Multivariate Adaptive Regression Spline (MARS) model and the Pelican Optimization Algorithm (POA) for bond strength prediction in this method. The input parameters include FRP width, FRP thickness, elasticity modulus of FRP, concrete strength, groove length, groove width, and groove depth, while the output is EBROG bond strength. The study demonstrates exceptional accuracy with R2 values of 0.9629 for training and 0.9623 for testing, highlighting the model’s precision. The proposed bond strength prediction equation for the EBROG method undergoes validation against existing models, encompassing thirteen equations for EBR and a recent one specific to EBROG. Statistical metrics confirm the accuracy and reliability of the proposed equation. Notably, FRP stiffness emerges as the parameter with the highest relative importance, while groove width exhibits the lowest impact on bond strength.

Dicing Process for 4H-SiC Wafers by Plasma Etching Using High-Pressure SF&lt;sub&gt;6&lt;/sub&gt; Plasma with Metal Masks

Since SiC is hard and brittle, dicing by normal grinding process not only requires a long time for processing, but also reduces chip strength due to microcracks. The use of highly efficient and damage-free etching with high-pressure plasma as a chemical processing method for dicing rather than mechanical processing was investigated. The results of groove processing using a combination of a metal mask with slit-like apertures and plasma etching with high-pressure SF6 plasma showed that the processing speed decreased with decreasing slit width and increasing groove depth. The results of electrostatic field calculations suggest that this is due to a decrease in plasma intensity caused by electric field decreasing.

Influence of beam polarization on underwater femtosecond laser machining of silicon wafer

This paper investigates the effect of polarization directions on underwater femtosecond laser machining of silicon wafer. Firstly, laser ablation in liquids produces laser-induced periodic surface structures (LIPSS) on both edges of the groove. The direction of LIPSS has direct correlation with the polarization of the laser beam. Secondly, the electric field intensity distribution within the groove is analyzed by numerical simulation employing the finite-difference-time-domain (FDTD) method. The simulation and experimental results reveal that the distribution of the inter electric field intensity within the grooves varies with polarization direction. As the angle between the polarization and scanning directions decreases, the peak electric field strength and groove depth gradually increase. Finally, changing the direction of polarization of the beam affects the symmetry of the groove profile. The groove profile produced by ablation is symmetrical when the beam polarization direction is parallel to the scanning direction. By modulating and optimizing the direction of polarization, grooves with large depth and symmetrical shape can be obtained.

Molecular dynamics study of the groove-forming mechanism of mechanically scratched grating multilayer aluminum films

For a long time, the forming quality of large area diffraction gratings is restricted by the one-time coating quality and uniformity of large thickness and large area aluminum films. Large thickness coatings, low accuracy of large depth grooves and diamond tool wear problems were the main reasons for the failure of the test to inscribe large area diffraction gratings. Therefore, the use of layered coating process can effectively ensure the uniformity and consistency of large-area and large-thickness grating blanks coated with aluminum film, and improve the high precision of large depth diffraction grating slot type. In order to reveal the mechanism of the groove-forming process of multilayer aluminum films, the microstructure and mechanical properties of different aluminum films were observed. In this article, the removal behavior and mechanism of nanomechanically scratched multilayer aluminum film materials are investigated using a molecular dynamics approach, and the characteristics of multilayer aluminum films scratched into grooves are analyzed in terms of surface morphology, scratching force, structural evolution, dislocation distribution, von Mises stress and shear strain. The results indicate that in the scratching simulation process, multilayer aluminum film has a higher number of removed atoms and a larger atomic displacement compared to single layer aluminum film, which is conducive to precise shape control of the groove. The average tangential force and normal force of multilayer aluminum film show a decreasing trend compared to single layer aluminum film, which helps to scratch grooves and reduce tool wear. The total length of the dislocation lines of the multilayer aluminum film is large, and the distribution area is large, which improves the precision of scratching the grooves. Therefore, an appropriate increase in the number of aluminum film layers has a precise control effect on the groove shape. This study has certain reference significance for analyzing the complex grooving deformation law of grating aluminum film, improving the diffraction efficiency of grating aluminum film, and further improving the manufacturing process of grating aluminum film.

Multi-objective optimization of liquid metal bearing based on NSGA-II

Due to their exceptional static and dynamic properties along with high-temperature resistance, liquid metal bearings are extensively employed in challenging environments. This paper carried out a multi-objective optimization work for spiral groove journal liquid metal bearings (JLMB) by using a NSGA-II. The clearance of bearing C, spiral angle a, groove depth hg, groove ridge ratio β, groove number N, and groove spacing P were chosen as design variables to maximize the load-carrying capacity and the effective stiffness of liquid metal bearing. During optimization process, the Latin hypercube sampling was adopted to generate 41 sample points, and the Kriging surrogate model was used to establish the correlations between design variables and objective functions. The Pareto front with optimal structures was obtained after optimization. Subsequently, optimal parameters were determined from the Pareto front by using the TOPSIS decision method. Finally, a comparative analysis of bearing performance was conducted between the journal liquid metal bearings with optimal parameters and the original parameters. The results indicated that the optimal JLMB parameters are given as follows: C = 10 μm, a = 26°, hg = 5.2 μm, β = 0.7, P = 11.1 mm, N = 10. The static and dynamic performance of optimized JLMB has been significantly improved. Specifically, the load carrying capacity increased to 2781.2N, making a 1313% enhancement over the JLMB with original parameters. While the effective stiffness of the optimized JLMB surged to 1.86 × 108 N/m, a more than 20-fold increase.

A novel multi-spot structure for joining aluminum and steel dissimilar thin-walled tubes by magnetic pulse crimping

Lightweight manufacture for dissimilar thin-walled tube structures without additional liner support has always been a challenge. A novel magnetic pulse multi-spot joining structure was proposed for the non-weight gain mechanical connection of 6061 aluminum to SPCC (Steel Plate Cold-rolled Common) steel thin-walled tubes. Mechanical properties, microscopic features, and joining mechanism of the magnetic pulse crimping (MPC) joints were explored based on simulation and experiments. Under the geometric conditions of flyer tube with an outer diameter of 30 mm and a thickness of 1 mm, the optimal preformed groove depth and discharge energy for the MPC joints were 2 mm and 16 kJ, respectively. The corresponding maximum tensile and torsional strength were 10.6 kN and 131.2 N m, respectively. The corresponding relative thinning rate of aluminum outer tube was 13 %. The failure forms of the MPC joints were all pull out and torsion out failures. During the high-speed joining of aluminum tube to steel tube, stress concentration phenomena occurred successively at the circumferential bottom fillet, axial bottom fillet, and axial upper edge of the groove. This was due to a certain height difference between the circumferential and axial directions of the groove. It was related to induction distance, discharge energy, skin effect, proximity effect, and tip effect in the coupled field. The yielding and instability of the groove in the steel inner tube would lead to a decrease in the fitting area of the aluminum outer tube filled groove and the relative thinning rate of the aluminum outer tube. This caused a decrease in the mechanical interlocking force at the groove, which was detrimental to the mechanical properties of the MPC joints. This article provides a new approach and data support for the lightweight manufacture of dissimilar thin-walled tube structures.

A novel microgroove-based absorber for sorption heat transformation systems: Analytical modeling and experimental investigation

This study proposes a novel sorber bed design, a stationary thin film microgroove-based absorber, that can address the low specific power and oversized sorber bed issues in existing oscillatory solid sorption heat transformation systems. An analytical heat and mass transfer model is developed for the proposed stationary thin film microgroove-based absorber. A highly-wettable microgrooved aluminum substrate is fabricated by the deposition of a hybrid Al2O3/TiO2 layer, and experimental water uptake measurements are obtained using a custom-built gravimetric large pressure jump setup to validate the analytical model. The model examines how key design parameters affect specific cooling power, cooling power density, and energy storage density. Findings indicate that cycle time and groove depth significantly impact system performance. Also, it is found that there is an optimum groove depth, or film thickness, to achieve maximum power. Trapezoidal grooves achieve higher specific cooling power and cooling power density, while rectangular grooves yield a higher maximum energy storage density. It is experimentally shown that a specific cooling power enhancement of up to 600 % can be obtained compared to the experimental data available for oscillatory sorber beds. Also, the absorption rate of the present sorber bed is up to three times higher than that of falling film absorbers.

Influence of Herringbone Grooves Inspired by Bird Feathers on Aerodynamics of Compressor Cascade under Different Reynolds Number Conditions

Nowadays, high aerodynamic load has made blade separation an issue for compact axial compressors under high-altitude low-Reynolds-number conditions. In this study, herringbone grooves inspired by bird feathers were applied to suppress the suction side separation and reduce loss. To study the effect of bio-inspired herringbone grooves on the aerodynamic performance of compressor cascades, a high subsonic compressor cascade was taken as the research object. Under the conditions of different Reynolds numbers, the effects of herringbone grooves of different depths on the flow separation were numerically studied. The research results show that at a high-Reynolds-number condition (Re = 5.6 × 105), the sawtooth-shaped wake induced by herringbone grooves increases the turbulent mixing loss near the suction surface, and the blade performance deteriorates. At a low-Reynolds-number condition (Re = 1.3 × 105), the span-wise secondary flow and micro-vortex structure induced by the herringbone grooves effectively suppress the laminar separation on the suction surface of the blade, and there is an optimal depth for the herringbone grooves that reduces the profile loss by 8.33% and increases the static pressure ratio by 0.55%. The selection principle of the optimal groove depth with the Re is discussed based on the research results under six low-Reynolds-number conditions.

Study on the Tribological Properties of Multilayer Concentric Hexagonal Laser Texturing on Rubber Surfaces of Screw Pumps.

Given the friction and drag reduction effects observed in various biological hexagonal structures in nature, a new design was implemented on the rubber surface of the stator of a submersible screw pump. This design featured a multilayer concentric hexagonal groove structure. Furthermore, a composite multilayer hexagonal structure integrating grooves and pits was also developed and applied. This study investigated the influence of groove layer number, groove depth, pit depth, and multilayer hexagonal groove texture arrangement on the rubber surface flow characteristics. Additionally, the pressure field state, the degree of influence on the oil film-bearing capacity, and the biomimetic and hydrodynamic lubrication theories were tested using the finite element analysis method. Tribological experiments were conducted on nanosecond laser-processed rubber textures under simulated liquid lubrication conditions, reflecting actual shale oil well experiments. These experiments aimed to investigate the influence of multilayer hexagonal shape parameters on the tribological characteristics of the stator-rotor friction pair of a submersible screw pump. The results indicated that with a constant overall size, a multilayer hexagonal structure with ~0.1 mm groove depth enhanced the oil film-bearing capacity, providing significant friction and drag reduction. For composite textures, a deeper pit depth within the study area enhanced the oil film-bearing capacity. Furthermore, a gradient arrangement of groove textures featuring wider outer grooves and shallower depth exhibited superior performance in terms of bearing capacity.

Numerical Simulation of Fishtail Biomimetic Groove for Dry Gas Seals

In recent years, the use of dry gas seal technology in high-end industrial applications has become increasingly widespread. Existing research has primarily focused on unidirectional grooves. This study introduces an innovative approach by incorporating bidirectional grooves inspired by the biomimetic design of a carp tail, aiming to enhance sealing performance. The analysis of flow-field characteristics was conducted using Fluent software to evaluate the effect of different groove designs on sealing efficacy. The results indicate that curved grooves are more effective in directing gas flow and reducing fluid dynamic losses, thus improving the overall sealing efficiency. In particular, the outer-curved carp-tail groove exhibited superior dynamic pressure effects and reduced pressure drops across various operating conditions. The optimal radial dam-to-groove width ratio ranged from 3.8 to 4.1, and the optimal groove depth ranged from 6.5 to 9.6 μm. This investigation focused on the design and performance evaluation of biomimetic carp-tail grooves for dry gas seals, presenting a novel groove configuration for end-face sealing and further advancing the theoretical understanding of dry gas seals.

Characteristics of Center-blast Tube with V-grooves During Blasting

The prediction of fracture time and crack development of metal shell under the impact load is a very significant research direction in engineering. In this paper, a coupling method is used to solve the dynamic expansion fracture process of center-blast tube with V-grooves under the pressure. A one-dimensional two-fluid model was utilized to govern the transient combustion. The nonlinear mechanical behaviors were predicted based on the finite element software ABAQUS, and the pressure and the structure were coupled by applying a user subroutine interface VUAMP in ABAQUS. The coupling approach was validated by comparing the predicted results with experimental results. Based on the validated approach, the characteristics of expansion fracture and the process of crack propagation on the center-blast tube with V-grooves were studied, and the effect grooves depth were analyzed. The results show that the crack propagation on tube can be divided into two stages that stable propagation stage and unstable propagation stage. The burst pressure of the center-blast tube with V-grooves decreases with the increase of crack depth, and the burst pressure decreases by about 7MPa with every depth increase of 0.25mm.

Simulation study on the radioactive logging responses in the spiral borehole

Abstract The spiral borehole, primarily attributed to uneven force on the drill bit, poses a unique drilling and well logging challenge. In certain logging applications, this phenomenon can disrupt logging responses, introducing periodic fluctuations in the logging curve and complicating the interpretation process. To elucidate the impact of the spiral-borehole phenomenon on conventional radioactive logging methods, we conducted a simulation study examining its effects on traditional density tool, thermal-neutron porosity tool, and natural gamma tool. Our findings reveal significant influences on density and porosity tool responses, with the amplitude of periodic fluctuations in logging curves closely linked to the groove depth of the spiral borehole. Conversely, the natural gamma tool exhibits minimal impact, with noticeable spiral-borehole effects causing limited fluctuations. Additionally, when the groove depth of the spiral borehole is fixed, the smaller the distance between the logging tool and the well wall, the closer the value obtained by the logging tool is to the true value of the formation parameter, and vice versa. This research offers theoretical insights for effectively correcting spiral-borehole effects in radioactive logging methods.

Analysis of Wear Characteristics of Hydrodynamic Seals During Startup Using 3D Fractal Characterization and Study of Opening Performance Degradation Mechanism

An experimental study was conducted to investigate the degradation mechanism of the opening performance of hydrodynamic seals during multiple startups, and a model was proposed to analyze the wear characteristics during the startup process. The study that the state evolution of the hydrodynamic seal during the single startup process occurs in five stages: low-speed and heavy-load stage, mid-speed and mid-load stage, high-speed and light-load stage, intermittent contact stage, and noncontact stage. The main factor that influences the deterioration of the initial performance of hydrodynamic seals during multiple startups is the decrease in the depth of the root groove. To prevent the heavy deterioration of the opening performance of the hydrodynamic seal, it is important that the remaining depth of the tip of spiral groove (TSG) is greater than 47.67% of the initial value and the dimensionless startup time should not exceed 0.42 for a complete passage through the mid-speed and mid-load stage.

Structural design and simulation of herringbone groove bearing lubricated with liquid metal

Abstract We designed a novel herringbone groove sliding bearing suitable for gallium-based liquid metal lubrication, taking advantage of the excellent fluidity, high thermal conductivity, and strong stability of gallium-based liquid metal at room temperature. We used the finite element method to analyze how eccentricity affected the bearing pressure variation and chose the best structural parameters by comparing how different groove parameters affected the peak pressure and carrying capacity. The results show that the herringbone groove reduces bearing friction resistance and causes the bearing pressure variation to exhibit a herringbone pattern. The herringbone groove structural parameters have a significant impact on the peak pressure and carrying capacity of the bearing. The gallium-based liquid metal bearing works well when the herringbone angle is 50°, the groove depth is between 15 μm and 25 μm, and the groove ratio is between 0.7 and 0.9.

A comparison of static and rotordynamic characteristics for two types of liquid annular seals with and without helical grooved stator

Less leakage is a benefit of parallel grooved liquid seals (labyrinth seals). But researches show that the liquid seal with parallel grooves on the rotor harms the rotor stability. The seal with helical grooves on stator performs well in terms of rotordynamics, and its leakage is sensitive to the rotating speed. To make use of the advantages of both seals and improve seal stability, based on the Smooth-stator/Parallel Grooved-rotor (SPG) liquid seal, a Helical Grooved-stator/Parallel Grooved-rotor (HGPG) liquid seal is designed. To evaluate two liquid seals’ leakage, rotordynamic characteristics and drag power loss, a transient computational fluid dynamics-based method is employed. This method is based on the multi-frequency elliptical-orbit rotor whirling model and the mesh deformation technique. The published experimental data of the leakage and rotordynamic force coefficients for an SPG liquid seal are used to validate the accuracy and dependability of the current method. Seal leakage and force coefficients are presented and compared for the SPG liquid seal and the HGPG liquid seal at various pressure drops. The influences of parallel groove depth on the leakage and rotordynamic properties for the HGPG liquid seals at two rotational speeds (2000, 6000 r/min) are analyzed. The numerical findings demonstrate that the novel HGPG liquid seal has a lower leakage flow rate (by ∼22.3%) than the traditional SPG liquid seal. There is an optimal parallel groove depth that minimizes leakage. The presented novel HGPG liquid seal significantly improves rotordynamic stability, due to the similar effective stiffness and the obviously larger positive effective damping. Reducing parallel groove depth can increase the positive effective damping. In terms of leakage and rotordynamic characteristics, the novel HGPG liquid seal is a better seal design for liquid turbomachinery.