Wu Wentao

Bio: Wu Wentao is an academic researcher from Qingdao University. The author has contributed to research in topics: Nozzle & Lubrication. The author has an hindex of 4, co-authored 16 publications receiving 141 citations.

Convective Heat Transfer Coefficient Model Under Nanofluid Minimum Quantity Lubrication Coupled with Cryogenic Air Grinding Ti–6Al–4V

Abstract: Under the threat of serious environmental pollution and resource waste, sustainable development and green manufacturing have gradually become a new development trend. A new environmentally sustainable approach, namely, cryogenic air nanofluid minimum quantity lubrication (CNMQL), is proposed considering the unfavorable lubricating characteristic of cryogenic air (CA) and the deficient cooling performance of minimum quantity lubrication (MQL). However, the heat transfer mechanism of vortex tube cold air fraction by CNMQL remains unclear. The cold air fraction of vortex tubes influences the boiling heat transfer state and cooling heat transfer performance of nanofluids during the grinding process. Thus, a convective heat transfer coefficient model was established based on the theory of boiling heat transfer and conduction, and the numerical simulation of finite difference and temperature field in the grinding zone under different vortex tube cold air fractions was conducted. Simulation results demonstrated that the highest temperature initially declines and then rises with increasing cold air fraction. Afterward, this temperature reaches the lowest peak (192.7 °C) when the cold air fraction is 0.35. Experimental verification was conducted with Ti–6Al–4V to verify the convective heat transfer coefficient model. The results concluded that the low specific grinding energy (66.03 J/mm3), high viscosity (267.8 cP), and large contact angle (54.01°) of nanofluids were obtained when the cold air fraction was 0.35. Meanwhile, the lowest temperature of the grinding zone was obtained (183.9 °C). Furthermore, the experimental results were consistent with the theoretical analysis, thereby verifying the reliability of the simulation model.

Temperature of Grinding Carbide With Castor Oil-Based MoS2 Nanofluid Minimum Quantity Lubrication

Abstract: Nanofluid minimum quantity lubrication (NMQL) has better stability, higher thermal conductivity, and excellent lubrication performance compared with traditional flood lubrication. The heat transfer model and finite difference model were established to verify the feasibility of NMQL conditions in grinding cemented carbide. Based on them, the grinding temperature of cemented carbide is calculated numerically. Results show that the grinding zone temperatures of flood grinding and NMQL are lower, 85.9 °C and 143.2 °C, respectively. Surface grinding experiments of cemented carbide YG8 under different working conditions are carried out. Dry grinding (227.2 °C) is used as the control group. Grinding zone temperatures of flood grinding, minimum quantity lubrication, and NMQL decrease by 64.2%, 39.5%, and 20.4%, respectively. The error is 6.3% between theoretical calculation temperature and experimental measurement temperature. Based on machining process parameters (specific grinding force, force ratio) and experimental results (microstructure of grinding wheel, workpiece, and grinding debris), the effects of different working conditions on wheel wear are studied. NMQL achieves the highest G ratio of 6.45, the smallest specific grinding force, and the smallest Fn/Ft ratio of 2.84, which further proves that NMQL is suitable for grinding cemented carbide.

Specific Energy and G ratio of Grinding Cemented Carbide under Different Cooling and Lubrication Conditions

Abstract: Workpiece surface integrity deterioration is a bottleneck in minimum quantity lubrication (MQL) grinding cemented carbide. However, nanofluids prepared by adding nanoparticles with excellent antifriction and antiwear properties achieve improved lubrication characteristics. In this study, a surface grinding experiment under four working conditions (i.e., dry, flood, MQL, and nanofluid minimum quantity lubrication (NMQL)) with cemented carbide YG8 is conducted to confirm the effectiveness of NMQL grinding. Results show that the minimum specific grinding force (Ft′ = 13.47 N/mm, Fn′ = 2.84 N/mm), friction coefficient (μ = 0.21), specific grinding energy (U = 17.02 J/mm3), and the largest G ratio of 6.52 are obtained using NMQL grinding. Furthermore, no evident furrow and large deformation layers are found on the surface of the workpiece. Moreover, the scanning electron microscope (SEM) images display that the debris is strip-shaped and slenderer than that under the other working conditions. Meanwhile, the blockage of the wheel pore is improved. Therefore, the validity of NMQL in grinding cemented carbide is verified.

Minimum quantity lubrication multi-freedom-degree intelligent spray head system based on CNC milling machine

Abstract: The invention discloses a minimum quantity lubrication multi-freedom-degree intelligent spray head system based on a CNC milling machine. The system comprises a CNC milling machine system connected with a nozzle multi-directional movement system and a nozzle angle automatic adjustment system. The nozzle multi-directional movement system comprises an XZ face rotation mechanism, a Y-direction movingmechanism and an X-direction moving mechanism. A nozzle is mounted on the X-direction moving mechanism and is further connected with the nozzle angle automatic adjustment system. The X-direction moving mechanism is used for driving the nozzle to move in the direction X. The nozzle angle automatic adjustment system is used for adjusting the angle of the nozzle. Under drive of the Y-direction moving mechanism, the X-direction moving mechanism can move in the direction Y along the Y-direction moving mechanism, and therefore X-direction movement of the nozzle is achieved. Under drive of the XZ face rotation mechanism, the X-direction movement mechanism can do XZ face rotation movement along the XZ face rotation mechanism, and therefore XZ face rotation movement of the nozzle is achieved.

Three-axis linkage platform based intelligent spray head system for minimum-quantity lubrication of numerical control horizontal lathe

Abstract: The invention discloses a three-axis linkage platform based intelligent spray head system for minimum-quantity lubrication of a numerical control horizontal lathe. A transverse moving portion is connected with a longitudinal telescopic portion to supply required power to transverse movement of the longitudinal telescopic portion, so that the longitudinal telescopic portion can move horizontally. Arotary portion is arranged in the longitudinal telescopic portion to enable the rotary portion to move longitudinally, is connected with a three-axis linkage platform and drives the three-axis linkage platform to rotate. Spray heads are arranged on the three-axis linkage platform, and detection devices are arranged on the spray heads. The transverse moving portion, the longitudinal telescopic portion, the rotary portion and the three-axis linkage platform are adjusted according to temperature data detected by the detection devices, so that the spray heads can achieve continuous tracking spraying when the horizontal lathe is used for machining. The three-axis linkage platform based intelligent spray head system for minimum-quantity lubrication of the numerical control horizontal lathe solves the problems of blind angles of cut surfaces and cutting fluid waste, and the spray heads can achieve continuous tracking spraying when the horizontal lathe is used for machining.