Bottom Of Grooves Research Articles

Research on the fabrication of high-quality patterned diamond using femtosecond laser

Diamond, known for its exceptional thermal, electrical, and mechanical properties, is widely used in precision machining tools, MEMS, and electronic devices. However, because of its extreme hardness and chemical inertness, diamond machining is highly challenging. Femtosecond laser technology, with its high instantaneous energy and minimal heat-affected zone, has emerged as an effective method for the precision machining of diamond. This study explores the application of 1026 nm and 513 nm femtosecond lasers in diamond grooving. The experimental results indicate that with increasing laser energy density, both groove width and depth increase, accompanied by a rise in amorphous carbon and graphite contents, resulting in increased tensile stress and decreased crystallinity in the machined region. Notably, the 513 nm laser demonstrates higher precision, achieving narrower grooves suitable for fine machining of diamond. Molecular dynamics simulations and experimental data reveal that the formation of amorphous carbon and graphite phases is the primary mechanism for deep ablation, and no significant anisotropy is observed during the process, allowing for the uniform fabrication of micro-nanostructures. TEM analysis confirms the presence of amorphous carbon and nanocrystalline diamond at the groove bottom, indicating phase transformation and also the formation of nanoscale diamond particles in regions of concentrated femtosecond laser energy. This study provides experimental and theoretical support for the high-quality fabrication of micro-nano structures on diamond, with significant implications for its advanced applications.

Fabrication of high-quality microlens arrays on fused silica based on combined rapid evaporative ablation and precision melting polishing of CO2 lasers

Microlens arrays (MLAs) made from fused silica possess broad applications in wavefront sensing, optical focusing, beam shaping, etc. However, it is challenging to fabricate the hard-brittle silica MLAs with high accuracy and low cost by conventional manufacturing techniques efficiently. In this work, a novel two-step method, which consists of rapid evaporative ablation and precision melting polishing by CO2 lasers, is proposed to fabricate high-quality MLAs. The first step is to rapidly ablate and engrave micro-pillar arrays (MPAs) with flat groove bottom by high-energy density CO2 lasers. The second step is to precisely polish and shape the flat-topped MPAs into the dome-topped MLAs with good surface roughness (Sa) by low-energy density CO2 lasers. The whole preparation process could be achieved through a set of machining system. Firstly, the geometric dimension (period, p and height, h) of the microlens is determined by the Monte Carlo ray tracing method. Secondly, to diminish the groove depth inconsistency caused by heat accumulation, the multiple ablation compensation strategy is developed. The MPAs (p = 200–400 μm), of which maximum height error is 7.1%, are prepared in 1 s by the proposed compensation strategy. Then, the MPAs are smoothed into the MLAs by low-energy density CO2 lasers, and the average Sa is improved from 960 nm to 32.56 nm. Finally, the optical performances of the MLAs are verified from the effectiveness of imaging, focusing and homogenization. The proposed two-step processing method paves a new way to fabricate high-performance MLAs on hard-brittle fused silica with low cost and high efficiency.

Anomalous intensification of vortex heat transfer in the case of separated air flow over an inclined groove in a hot isothermal region of a flat plate

Anomalous heat transfer intensification in turbulent separated air flow over a long groove of moderate depth made in a plate inclined at an angle of 45°to the freestream is revealed both experimentally and numerically. The region under investigation includes a rectangle heated to 100°C by saturated water vapor. The Reynolds number varied from 103to 3×104. Using the gradient heatmetry the twofold increase, as compared with the case of a flat plate, of the heat transfer coefficient on the groove bottom is established at the Reynolds number Re = 3×104. The relative Nusselt number in different regions of the groove is determined both in the physical experiment and in the RANS calculations with the application of multiblock computational technologies and the SST model in the VP2/3 software package. The results are in good agreement in the turbulent flow regime at Re = (5, 10, and 30) ×103.

Mechanical Abrasion of Laser‐Machined Highly Hydrophobic Stainless Steel Surface Depending on Surface Topography

Stainless steel (SST) is an important material for a variety of applications including construction, food, and medical. Highly hydrophobic wetting properties enhance the surface properties of SST to support processes such as self‐cleaning . However, applications also require long‐term stability of such properties against chemical and mechanical influences from the environment or technical processes. Therefore, the reduction of highly hydrophobicity of chemically modified, laser‐textured SST surfaces is investigated in relation to abrasive wear using hierarchical structures, micro‐/nanotextured surface, and support structures that shield the highly hydrophobic pattern. Surface textures comprising ridges, grooves (size: 50–500 μm; depth: up to 100 μm), and a nanostructured grooves bottom are machined by infrared ultrashort pulse laser ablation into SST and are subsequently chemically modified by a self‐assembled monolayer of a fluorinated, phosphonic acid‐modified alkane. Abrasive wear tests of these surfaces show decreasing water contact angles with increasing wear of the modified surface of the support structures. However, there is good stability of the highly hydrophobic properties due to the protection of modified areas at the groove bottom. The proposed wetting model for such designed functionalized laser textures shows possibilities for further optimization of such robust highly hydrophobic surfaces and adaptation to specific applications.

Nonlinear Impact Damage Evolution of Charpy Type and Analysis of Its Key Influencing Factors

The current research of Charpy impact mainly focuses on obtaining the ductile brittle transition temperature of materials by experiments. Compared with experiments, numerical simulation can study many problems with harsh conditions. However, there are still few studies on the influence of geometric factors such as side grooves. In this paper, the geometry of standard Charpy impact test is designed. Specimens with different widths and side grooves are tested. The finite element model of Charpy impact was established by ABAQUS software. Use test results and simulation results to verify each other. The effects of sample width, side groove depth and side groove bottom fillet on the impact fracture resistance of the sample were studied. The results show that the specimen width is positively correlated with the impact toughness of the specimen. The side groove greatly reduces the impact toughness of the material; the toughness of side groove decreases with the increase of depth; the fracture toughness of side groove decreases with the increase of fillet at the bottom of side groove. The proportion of toughness energy to impact energy of samples was analyzed. The results show that the toughness energy accounts for about 70% of the impact energy of the sample, which has little to do with the geometric characteristics of the sample. This study presents a reliable method for studying Charpy impact tests. The influence of geometric parameters is obtained, which provides a reference method for the study of impact toughness of high toughness materials.

Keyhole stability, arc behavior, and molten pool flow in narrow-gap oscillating laser-arc hybrid welding of titanium alloy

In the study, the keyhole stability, arc behavior and molten pool flow were investigated to clarify the welding process stability in narrow-gap oscillating laser-arc hybrid welding of titanium alloy. At an oscillating frequency of 300 Hz and amplitude of 1 mm, a concave weld with low porosity was produced. Compared with non-oscillating laser, the keyhole opening size increased about twofold, and the standard deviation of arc deflection angle differences decreased by approximately 87.6 %. Owing to the stirring effect of beam oscillation, a stable keyhole with larger opening size was formed, which facilitated the escape of bubbles from the keyhole. More excitation electrons were generated and erupted outward from the keyhole, and both plasma temperature and density increased by approximately 55.2 %. An enhanced electric channel was formed between the welding wire tip and groove center. As a result, the arc burnt stably at the groove bottom, which could melt the groove bottom synchronously, and suppress sharp corners and lack of fusion. The impact caused by droplets was cushioned as the liquid metal flowed towards the rear molten pool orderly with a circular path. Consequently, the liquid metal near the keyhole fluctuated slightly, indicating that the keyhole stability was enhanced. Besides, dendrites were fragmented and more equiaxed grains were produced due to the strong disturbance of dendrites by liquid metal in the whole mushy zone.

Analysis of the microscopic characteristics of periodic structure arrays on silicon carbide fabricated by femtosecond laser

The fabrication of large dimension structures (800 μm × 800 μm) featuring fine and coarse ripple patterns, nano particle structures, and V-shaped grooves was achieved on silicon carbide (SiC) through the use of femtosecond laser. The X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy (Raman) were performed on sample surface to investigate the atomic bond, residual stress and lattice disorder. XPS analysis revealed that an increase in laser fluence resulted in an increase in the content of C=O bond, while the content of O–C=O bond decreased. The C–C (sp2) bond was destroyed, while the unstable C–C (sp3) bond increased. Additionally, there was a decrease in the content of Si–Si bond and Si–C bond, and an increase in the content of Si–O bond. The resulting oxide layer contributed to an improvement in the fracture toughness of the periodic array. XRD analysis results indicate that the technique is not sensitive to structural defects in SiC and surface contaminants caused by laser ablation. On the (0008) crystal plane, an increase in fluence resulted in an initial increase in lattice spacing, strain, and residual stress, followed by a plateau. The laser-modified area corresponded to a region of tensile stress, with the maximum tensile stress being 179.464 MPa. On the (0004) crystal plane, an increase in fluence resulted in varying degrees of increase in lattice spacing, strain, and residual stress. The residual tensile stress at the fine ripple and groove bottom was 0 and 14.623 MPa, respectively, while the residual tensile stress at the coarse ripple and nano particle structure was 277.847 MPa. The residual tensile stress increased with an increase in scanning interval. Raman analysis showed that the overall disorder increased with an increase in laser fluence, with a maximum degree of disorder being 0.548.

GEOMETRIC CLAMPING PLATE DIMENSIONS OF THE IMPROVED OF GRAIN SEEDER COULTER SZ-3,6

The article notes that the improvement of operating tools of sowing machines is a solution to one of the many tasks of increasing crop yields. It is also noted that a two-disc coulter and its inherent advantages and disadvantages have been widely used on sowing machines, and the final sowing operation is considered the most important for seeds, since it creates conditions for their germination and further development.
 Significant factors affecting the germination and development of plants after sowing with seeders equipped with disc coulters are given, one of which is the tight contact of seeds with the bottom groove with a loose surface layer.
 The scheme for improving a two-disc coulter with pressure plate installed in the inter-disc space is proposed, and the details of the coulters are maximally unified with the coulters of grain seeders of the type SZ-3.6, mass-produced by domestic manufacturers. The pressure plate, moving together with the coulter, crushes small soil lumps with the inclined part and pushes the seeds into the bottom groove with a horizontal shank, ensuring their tight contact with the soil. A method for determining the main geometric parameters of the pressure plate depending on external forces acting from the soil is proposed, the dependence of the characteristics of the cross-section of the plate on the geometric dimension is given

Influence of the axial load ratio on the mechanical behaviour of prefabricated concrete shear walls with Mortise–Tenon joints

Prefabricated concrete shear walls with mortise–tenon joints (MTJ shear walls), as innovative fully prefabricated concrete shear wall structures without extended reinforcements, can meet the development needs of the current construction industry in China. One cast-in-place concrete shear wall and four MTJ shear walls with different axial load ratios (ALRs) were tested by performing pseudostatic tests. The mechanical behaviour of the MTJ shear walls and the influence of the ALR were studied. The test results show that the construction of the mortise–tenon joint in the MTJ shear walls was reasonable and that the connection was reliable. The failure process of the MTJ shear walls was different from that of the cast-in-place concrete shear wall. Vertical cracks formed along the bottom of the transverse grooves, which weakened the integrity of the MTJ shear wall and contributed to improving the deformability. The damage to the MTJ shear walls was mainly concentrated around the mortise–tenon joints, resulting in a reduction in the concrete crushing area at the root of the cast-in-place concrete boundary elements (CBEs) on both sides of the shear wall. With an increase in the ALR, the yield load and peak load of the MTJ shear wall gradually increased, but the displacement ductility coefficient decreased. However, when the test ALR was 0.30, the displacement ductility coefficient of the corresponding MTJ shear wall still reached 3.73, exhibiting good deformability. Reasonable numerical analysis models were established with ABAQUS to systematically analyse the influence of the ALR on the mechanical behaviour of MTJ shear walls. The ALR limit value of the MTJ shear wall was recommended to be 0.45.

Effect of Load on Surface Roughness of PPS Thrust Bearings under Rolling Contact Fatigue in Water

Rolling bearings are important mechanical parts. They are used for the transmission of rotational motion. In this study, we focused on surface roughness of the polymer thrust bearing under rolling contact fatigue. Surface roughness of the groove bottom was measured when small pitting around shoulder and crack occurred. Thrust bearings were loaded with thrust loads of 2300 N, 2400 N, 2500 N, and 2600 N. The surface in the rolling contact area was worn during the rolling contact fatigue test. We concluded that surface roughness values ranged from 0.49 μm to 0.18 μm, under thrust loads of 2300 N, 2400 N, 2500 N, and 2600 N when small pitting occurred.

A comparison of the swing and non-swing arc behavior in arc ultrasonic assisted narrow gap GMAW

The arc ultrasonic technology was applied to the swing arc narrow gap GMA welding process of aluminum alloy. The ultrasonic energy acts on the welding process by superimposing an ultrasonic current on the basis of pulsed welding current. The arc behavior will be significantly different from that in the conditions of non-narrow gap and non-swing due to influences from the narrow gap groove constraint and the arc swing. In this paper, the behavior of swing arc and non-swing arc at different positions in narrow gap groove are compared, and the influence mechanism of arc ultrasonic on arc behavior is analyzed. Results indicate that the arc expands after superposition of ultrasonic current, and that the arc behavior is different at different positions of the narrow gap groove. In the sidewall, the expansion degree of the non-swing arc is obviously greater than that of the swing arc. The swing arc area increases by 50.33% at most, and the non-swing arc area increases by 117.94% at most. In the groove bottom, the expansion degree of the swing arc is greater than that of the non-swing arc. The average area and width of the swing arc in the groove are nonlinear relationships with the ultrasonic current amplitude and a linear positive correlation with the ultrasonic frequency, respectively. Arc swing and ultrasonic action make the arc length longer. The difference in speed between arc expansion and contraction and the oscillation of arc plasma under the arc ultrasonic action together promote arc expansion.

Optimization with Taguchi Method of Laser Parameters Necessary for Smooth Groove Bottom in ZAMAK 5

In this study, groove-shaped cavities were created with Nd: YAG laser on ZAMAK 5 plates, which have been used frequently in the industry for many years. The necessary laser parameters have been optimized so that the created cavity floor has a homogeneous depth. The effects of the beam diameter, laser energy, shielding gas type, and duration of the single pulse of Nd: YAG laser used on the roughness in the cavity were tried to be optimized. It was used for optimization. According to the ANOVA table, the optimum parameters are “580µm, 7J, Nitrogen, 7 ms for spot diameter of spot, the energy of single spot, type of ambient gas and a spot of single pulse respectively. The Taguchi method also indicates how effective the laser parameters used are in obtaining the desired surface. It has been concluded that the ambient gas used is the most important parameter in this study. The effect rate was obtained as 74.90 %. Then, laser spot diameter and pulse energy and lastly pulse duration are fewer effective parameters respectively.

Finite element analysis of optimal design of distal geometry of cementless femoral prosthesis.

This study aims to improve the geometric design of the distal cementless femoral prosthesis stem, thereby changing the stress distribution of the femoral prosthesis and reducing the proximal stress shielding and distal stress concentration of the femur, so as to obtain better bone growth and long-term stability. Two geometric shapes of the femoral stems, namely, inverted hollow cone and cross-shaped bottom groove, are designed for the distal femoral prosthesis. The model is built based on the femoral computed tomography (CT) data of healthy volunteers, and the finite element method is used to analyze and calculate the stress distribution of the two femoral prosthesis stems. According to the length and width of bottom "cross" groove, the stress values of the femoral region of the cross-grooved distal femur are divided into five groups, namely, group 1 (length 1:1, groove width 1.0 mm); group 2 (length 1:1, groove width 1.5 mm); group 3 (length 1:1, groove width 2.0 mm); group 4 (length 1:2, groove width 1.0 mm); group 5 (length 1:2, groove 1.5 mm wide). And the non-grooved group of the distal femur is designated as group 0. In the segment A, B, and C of the femoral region, the difference in the mean stress between group 0 and groups 1, 2, and 3 have statistical significance. The bottom "cross" groove of the distal femoral prosthesis can change the stress distribution in the prosthesis-distal femoral region and reduce the stress concentration at the distal prosthesis. Wherein, the grooved design of length ratio 1:1 is more advantageous.

Design of Nonsmooth Groove Tire Bioinspired by Shark-Skin Riblet Structure.

As one of the major causes of traffic accidents on wet roads, hydroplaning is prone to occur when the traveling speed of a vehicle rises so high that the hydrodynamic pressure between pavement and tires equals inflation pressure. In this condition, the vehicle nearly loses braking and steering capacity. Inspired by the superior drag reduction function of shark-skin riblet, the purpose of this study is to arrange bionic nonsmooth structures at the bottom of longitudinal grooves to promote the hydroplaning performance without affecting other tire performances. A finite element model of 185/60R15 tire was employed and its accuracy was verified by loading tests with CSS-88100 electronic testing instrument. Meanwhile, a fluid domain model was founded by computational fluid dynamics (CFD) method. The simulated critical hydroplaning speed was in accord with that obtained by the NASA empirical formula. Inspired by shark-skin riblet, three kinds of nonsmooth surfaces were exploited. In addition, the drag reduction rate, shear stress, and flow velocity distribution were compared for different grooves. Then, the optimized nonsmooth structure with the best drag reduction effect among three nonsmooth surfaces was arranged at the bottom of longitudinal grooves for bionic tire. Simulation results demonstrated that the bionic tire obviously decreased hydrodynamic lift and increased flow velocities. With these improvements, the critical hydroplaning speed was effectively improved for the bionic tire. These research results can be applied to the promotion of hydroplaning performance without degrading other tire performances.

Narrow-gap laser welding with beam wobbling and filler wire and microstructural performance of joints of thick TC4 titanium alloy plates

How to control poor fusion of sidewall and interlayer in narrow-gap laser welding with filler wire of thick plates is an unsolved problem. When the groove width changes in the direction of the plate thickness (for example, V-shaped narrow-gap grooves or preset inverse deformation to offset angular distortion caused by welding), incomplete fusion is more difficult to control, resulting in low yield. Laser welding with beam wobbling and filler wire (LWBWFW) was carried out on narrow-gap butt joints of thick TC4 titanium (Ti) alloy plates with V-shaped grooves. On this basis, the relationship between welding conditions and incomplete fusion under four widths of the groove bottom (4, 6, 8 and 10 mm) was studied. It is found that the key to eliminating incomplete fusion is shown as follows: on the one hand, the beam wobbling amplitude should be appropriate. On the other hand, the ratio of the welding line energy to the wire feed amount should be proper. The former mainly affects incomplete sidewall fusion, while the latter mainly influences incomplete interlayer fusion. Following the above principles, this research obtained well-formed joints of TC4 alloy with the thickness of 30 mm welded by LWBWFW (hereinafter referred to as LWBWFW joints) and the tensile strength of the joints can reach 99.6% that of base metal (BM).

ПРИМЕНЕНИЕ СКАНИРУЮЩЕЙ ТУННЕЛЬНОЙ МИКРОСКОПИИ ДЛЯ ОЦЕНКИ СТЕПЕНИ НЕРАВНОВЕСНОСТИ ГРАНИЦ ЗЕРЕН В НИКЕЛЕ, ПОЛУЧЕННОМ КРУЧЕНИЕМ ПОД ВЫСОКИМ ДАВЛЕНИЕМ

The goal of the study is to estimate the relative free energy of grain boundaries in nickel deformed by high-pressure torsion (HPT) using scanning tunneling microscopy. In the process of work, the following studies have been carried out. The technique has been developed for sample preparation of Ni samples subjected to severe plastic deformation (SPD) by the HPT method for subsequent studies by scanning tunneling microscopy, which provides an average value of the root-mean-square surface roughness of approximately 2 nm. Using scanning tunneling microscopy, images of the nickel surface structure have been obtained, which have been processed using the Gwyddion application program. As a result, the grain boundary profiles have been calculated, based on which the values of the dihedral angles at the bottom of the etching grooves have been calculated and the relative energies of the grain boundaries have been calculated. It has been established that after HPT deformation, the average relative energy of grain boundaries significantly exceeds the relative energy of grain boundaries of coarse-grained nickel with grain boundaries of recrystallization origin. Thus, because of HPT, non-equilibrium grain boundaries are formed in the samples. It has been shown that with an increase in the degree of HPT deformation, an increase in the average relative energy of grain boundaries occurs, which indicates an increase in the degree of their non-equilibrium. It has been demonstrated that SPD by the HPT method makes it possible to achieve a higher level of relative energy of grain boundaries than deformation by the equal-channel angular pressing (ECAP) method.

Construction simulating and controlling of the two-well-vertical(TWV) salt caverns with gas blanket

The two-well-vertical (TWV) cavern-constructing with gas blanket technology is an important alternative to the single-well (SW) with oil blanket technology. This technology has the advantages of achieving larger cavern volume, clean brine, great water flow rate, and high economic benefits. Promoting and developing its theory and technology will help the future development of salt mining and cavern construction for energy storage in China, as it is in the initial stage. In this paper, a visualized physical simulation platform of water dissolving of the TWV caverns with gas blanket was established, and large size salt rock blocks were used to simulate the constructing process of salt caverns. The similarity ratios of size, flow rate, and time between prototype and model were calculated by using the similarity theory and dimensional analysis. A series of physical simulation tests of water-dissolving caverns were carried out, that the research factors including the two-well-spacing, flow rate, and gas/oil blanket. The results show that: (1) The water flow rate can be increased to 200–400 m3/h by increasing the two-well-spacing when using the TWV technology, which is 2–4 times that of the single-well. (2) It is found that 30–40 m is the optimal size for the two-well-spacing, and the two-well-space is much larger than 40 m may exist risks of roof instability. (3) During the initial stage of cavern construction, it will obtain a smaller lateral solution angle and an ideal cavern bottom groove shape with gas blanket. After the cavern construction is finished, it also will obtain better cavern shape, larger cavern volume and clean brine by comparing with oil blanket. So, the technology of the TWV cavern construction with gas blanket is promising for brine leaching and energy storage cavern construction and it is also worth further study.

Super-regular femtosecond laser nanolithography based on dual-interface plasmons coupling

Abstract Advances in femtosecond laser-material interaction facilitate the extension of maskless optical processing to the high efficiency and deep-subwavelength scale. Here, a hybrid plasmon lithography technique has been demonstrated by irradiating near-infrared femtosecond laser pulses onto the Si material coated with thin Cr films in a vacuum chamber, and superior nanograting structures are found to deeply penetrate through the thin Cr film into the underlying Si substrate. In stark contrast to the common ripple structures formed on the Si surface, the Cr-layer mediated Si nanograting structures not only exhibit the spatially super-regular arrangements with a deep-subwavelength period of 355 nm but also present the nonsinusoidal sharp-edged groove geometry with a large depth-to-width aspect ratio of 2.1. Theoretical analyses and calculations reveal that the anomalous structure characterizations are physically ascribed to the excitation of dual-interface coupled plasmons in the thin metal layer, which possess the squeezed spatial wavelength and the periodic columnar intensity distributions. Moreover, the further deepening of periodic nanostructures into the Si substrate is also elucidated by the simulation of electric field enhancements at the bottom of shallow grooves under irradiation of subsequent laser pulses. In combination with a wet etching process, the Si nanograting structures can be modified into the smooth and narrow-mouthed V-profiles, whose optical measurements show a near omnidirectional antireflection especially in the visible range of 565–750 nm, which is expected for the design of advanced photonic devices.

Experimental and numerical study on lateral resistance of frictional sleeper with arrowhead groove

To enhance the stability of continuous welded rail (CWR) tracks, frictional sleepers have been developed. The frictional sleepers are new types of sleepers with grooves on the bottom, and different bottom grooves improve lateral resistances at different magnitudes. In this study, single sleeper push test (SSPT) and its model with discrete element method (DEM) were carried out to confirm how much arrowhead groove frictional (AGF) sleeper increases the lateral resistance of ballasted track. The SSPTs were performed to confirm the lateral resistance results, and also to validate and calibrate the DEM models. With the validated models, the groove factors influencing the lateral resistances were studied, including groove sizes (depth, width), arrowhead groove direction and groove numbers. The reason of lateral resistance improvement was studied at mesoscopic level, including the ballast-sleeper contact numbers and contact force chains. Results show that applying the AGF sleeper is able to improve lateral resistance by 7–24%, and it can provide enough lateral resistance after reducing ballast shoulder width from 500 mm to 300 mm. The AGF sleeper can improve the sleeper-ballast interaction by increasing sleeper-ballast contact number. The study is helpful for frictional sleeper design, further improving track stability.

Study of the thermo-mechanical couple deformation of the meshing pairs of a single-screw compressor

Single-screw compressor has attracted attentions from the scientific community due to its excellent performance. However, thermal deformations of the star wheel, screw, and casing substantially affect the clearance between the components, and hence reduce the performance of the single-screw compressor. In this study, the thermal deformation of a meshing pair of the single-screw compressor was investigated using a finite-element-based thermo-mechanical coupled model. This model was developed based on measured thermal boundary conditions during compressor operation. The effect of thermal deformation on the compressor sealing clearance was then studied. The results showed that the thermal deformation of the casing, screw, screw shaft, and star wheel significantly affected the clearance between the tooth tip and the groove bottom as well as the meshing pair clearance distribution. The change of clearance between the casing and screw is up to 0.03 mm while the change of the clearance between the star wheel tooth tip and screw groove is up to 0.05 mm. Furthermore, it was found that the spatial position meshing error caused by the thermal deformation was one of the major reasons for the wear of the meshing pair of the single-screw compressor. The simulated thermal deformation results agreed well with the experimental data. The clearances of the compressor were modified based on the thermal deformation in a single-screw compressor with a capacity of 6 m3/min and the results showed that the modified compressor can operate reliably. This indicated that the developed model could be used in the design of the single-screw compressor. It provides guidance for the design and optimization of large single-screw compressors.