Nozzle Coolant Research Articles

Research on effect of ultra-high pressure coolant supplied from flank face in end milling of Ti-6Al-4V supported by CFD simulations

In end milling of difficult-to-cut material such as Ti-6Al-4V, thermal wear is one of the main reasons leading to short tool life. High temperature occurred at the cutting zone during cutting process advances adhesion wear and diffusion wear at rake face, accelerates thermal plastic deformation. Furthermore, high temperature could also accelerate flank wear and promote adhesion wear at flank face. Consequently, machining precision of tool will degrade. Ultra-high pressure coolant (UHPC) is one of the well-known cooling/lubrication methods to solve this problem. In this paper, effect of UHPC on end mill flank face have been studied. To accomplish this, we designed an end mill with flank face coolant supplied from a close distance. The influence of coolant nozzle's direction has been studied by computational fluid dynamics (CFD) simulations. The result explains how the direction of the coolant nozzle impact on flow condition on the tool surface. The end mill was manufactured based on simulations by additive manufacturing. Experimental results including flank wear, surface roughness and cutting temperature demonstrate advantages of UHPC in end milling compared to dry cutting and flood coolant. The micro morphology of the worn areas on flank face and rake face further supports the advantages of UHPC.

An investigation of additively manufactured coolant nozzles for cylindrical grinding applications and progression to high stock removal

This paper explores use of Additively Manufactured features in coolant nozzles for cylindrical grinding applications. In an external cylindrical grinding process, different stock removal rate regimes are trialed to assess printed nozzle features; 3D printed nozzles with special internal features are shown to generate an improvement in key surface roughness metrics (up to 0.3 µm Sa reduction in mean area surface roughness) and superior wheel condition in Q’ ≤ 2.61 mm2/s cylindrical plunge grinding applications. In addition, use of VIPER grinding principles achieved a stable cylindrical grind at Q’ = 20.47 mm2/s using a porous wheel and hook nozzle tooling.

Studies on Eco-Friendly Grinding with an Extremely Small Amount of Coolant – Applicability of Contact-Type Flexible Brush-Nozzle –

This study considers an innovative coolant nozzle that enables a remarkable reduction in grinding fluid consumption in cylindrical plunge grinding of chromium molybdenum steel (ISO 34CrMo4 / JIS SCM435) using a vitrified-bonded cubic boron nitride (CBN) wheel. This coolant nozzle has a simple structure consisting of ordinary nylon or polypropylene fiber brushes and an acrylic resin oil pool. This flexible brush-nozzle is suitably placed in contact with the wheel surface, and the grinding fluid is supplied along the brush to the wheel surface to form a fluid film to the wheel surface, while simultaneously scraping the “air belt.” Thus, the grinding fluid adheres to the whole wheel surface by the “Coandă effect,” and grinding fluid consumption is reduced to 0.5 L/min or less without causing any thermal damage to the ground surface. The cooling effect of this coolant nozzle is examined mainly by a grinding temperature measurement by means of a fiber-coupled two-color pyrometer. The nylon fiber brush is more effective than the polypropylene brush because of its high elasticity and good water absorption rate, which is related to the wettability. Even with such an extremely small amount of grinding fluid, the grinding force, surface roughness, and grinding temperature are nearly the same as those in the case of the conventional wet grinding.

Incidence Effect on the Aero-Thermal Performance of a Film Cooled Nozzle Vane Cascade

In the present paper, the influence of inlet flow incidence on the aerodynamic and thermal performance of a film cooled linear nozzle vane cascade is fully assessed. Tests have been carried out on a solid and a cooled cascade. In the cooled cascade, coolant is ejected at the end wall through a slot located upstream of the leading edge plane. Moreover, a vane showerhead cooling system is also realized through four rows of cylindrical holes. The cascade was tested at a high inlet turbulence intensity level (Tu1 = 9%) and at a constant inlet Mach number of 0.12 and nominal cooling condition, varying the inlet flow angle in the range ±20 deg. The aero-thermal characterization of vane platform was obtained through five-hole probe and end wall adiabatic film cooling effectiveness measurements. Vane load distributions and surface flow visualizations supported the discussion of the results. A relevant negative impact of positive inlet flow incidence on the cooled cascade aerodynamic and thermal performance was detected. A negligible influence was instead observed at negative incidence, even at the lowest tested value of −20 deg.

Numerical study on flow and heat transfer behavior of vortex and film composite cooling

The complete vortex and film composite cooling model is established to study the flow and heat transfer behavior. Influences of coolant Reynolds number, film hole diameter and inject angle on vortex and film composite cooling property are thoroughly discussed. Results show that the vortex nozzle coolant mass flux increases along the vortex chamber axial direction, while the film hole coolant mass flux and blowing ratio decrease along the vortex chamber axial direction. The internal heat transfer intensity will increase along the vortex chamber axial direction. The adiabatic film cooling efficiency decreases downstream due to counter rotating vortex pairs (CRVP) lift off wall effects. The coolant rotational velocity in vortex chamber increases with the increasing Reynolds number, thus leading to obvious heat transfer enhancement. An increase in Reynolds number results in an increase in CVRP intensity, hence the adiabatic film cooling efficiency will turn lower. The coolant rotational velocity and internal heat transfer intensity will decrease with the increase of film hole diameter. The CRVP intensity and film hole jet coolant mass flux increases with the increasing film hole diameter, leading to an increase in adiabatic film cooling efficiency. The rotational coolant flow and heat transfer intensity are not sensitive to inject angle. As the inject angle increases, the CRVP intensity changes little and the inject coolant owns larger inclined angle with gas mainstream flow, therefore the adiabatic film cooling efficiency will increase.

Prediction of the convective heat transfer coefficient of cutting fluid in helical drills

Environmental, economical and social factors impose the elimination or reduction of the quantity of the cutting fluids used in the machining. This trend leads to a high temperature in the cutting zone. In drilling, when the cutting fluid is not supplied through the spindle, the tool tip suffers from high temperature, leading to rapid wear. In this case, the cooling of the drill tool body can contribute significantly removing the heat generated at the tool–chip interface. However, to effectively simulate the temperature at the tool tip, the effect of the cutting fluid on tool body must be known. Hence, the aim of this work was to determine the convective heat transfer coefficient of the cutting fluid on the complex body of a helical drill. In this regard, a special experimental setup is developed, allowing the drill to remain static while the coolant nozzle rotates around providing cutting fluid. A method is developed in order to determine the temperature on the drill surface as a function of the heat enters into the drill and the temperature measured at the tool base. Experiments are carried out varying coolant nozzle rotation speed and the cutting fluid flow rate. According to the results, the cutting fluid flow rate shows to have the most significant effect on the convective heat transfer coefficient.

Effect of CNC Lathe Machining Performance by Varying Coolant Nozzle Diameter

Background/Objectives: The cutting temperature is important in machining process. The temperature is a most common effect base on cutting parameters such as cutting speed, feed rate and depth of cut. Optimization of the cutting parameter can also reduce of heat temperature. This way can reduce cost and also can produce a good quality of production. Method/Statistical Analysis: In this study focus on effect of machining the aluminum alloy AL6061 by using a various diameter coolant nozzle during CNC lathe process of its inherent advantages. Hence, it also studies the effect of cutting temperature to the surface roughness and dimensional error that will be considered with the parameters to arrive at a conclusive result. Taguchi method orthogonal array L16’ was selected as an experimental plan for turning on AL6061 by using CNC PUMA 230 turner with carbide tool insert. The L16’ array used 5 factors and 4 levels in conduct the temperature measurement. Findings: Results show that the dominant failure mode is the surface roughness and dimensional accuracy when the nozzle orifice size increases during machining of aluminum alloy AL6061. The exploration for dimensional accuracy, productivity and the optimization of cutting speed in the technical and commercial aspects of the manufacturing processes of aluminum AL6061 are discussed in oil and gas components industries for further work. Applications/Improvements: Conclusion and recommendations will suggest an enhancement to this application.

Effect of Coolant Nozzle Sizes on Turning Aluminum Alloy AL319

Background/Objectives: The paper discusses about the optimum cutting parameters with combination of various sizes of nozzle coolant to optimize the surface roughness, chips deformation and dimensional accuracy in the turning process based on the selected setting parameters. The selected cutting parameters for this study were the cutting speed, feed rate, depth of cut and various diameters of nozzle coolant. Methods/Statistical Analysis: Experiments were conducted and investigated based on Design of Experiment (DOE) with Taguchi method. The research of the aggressive turning process on aluminum alloy (A319) for automotive applications is an effort to understand the high speed machining concept, which widely used in a variety of manufacturing industries especially in the automotive industry. Findings: The results show that the dominant failure mode is the surface roughness and dimensional accuracy when the nozzle orifice size increases during machining of the A319. The exploration for dimensional accuracy, productivity and the optimization of cutting speed in the technical and commercial aspects of the manufacturing processes of A319 are discussed in automotive components industries for further work. Applications/Improvements: The result of this study shows that the effectiveness and efficiency of the system can be identified and helps to solve potential problems.

Turbine Blade Surface Phantom Cooling from Upstream Nozzle Trailing-Edge Ejection

This paper presents upstream nozzle trailing-edge coolant ejection on downstream uncooled blades. A pressure-sensitive paint mass transfer technique provides detailed phantom cooling effectiveness distribution on modeled land-based turbine rotor blade surfaces. Without cavity purge and tip leakage flows, a uniform blade inlet temperature is adopted in the current study. Experiments have been completed in a low-speed wind-tunnel facility with a five-blade linear cascade. The inlet Reynolds numbers based on chord length are 100,000 and 200,000. Nozzle trailing-edge coolant ejection on a rotor blade is simulated by a spoked-wheel-type rotating facility with 32 hollow rods equipped with coolant ejection from 128 holes per rod. Coolant to mainstream density ratio maintains at 1.5 to match engine conditions. Nozzle coolant discharge velocity to nozzle mainstream velocity ratio varies from 0.4 to 1.4. Velocity ratios from 0.4–0.6 are closest to typical engine conditions. Coolant to mainstream mass flow rate ratio effect is from 0.67 to 2.94%. Higher phantom cooling effectiveness occurs on suction and pressure surfaces at the velocity ratio of 0.4–0.6 and over 1.0, respectively. Velocity ratio effect impacts phantom cooling effectiveness distribution more than the mass flow rate ratio effect. Most of the trailing-edge coolant migrates toward blade inner and outer spans than the blade midspan.

Metodyka projektowania wysokociśnieniowych dysz chłodziwa

Metodyka projektowania wysokociśnieniowych dysz chłodziwa

Projektowanie i analiza MES kształtowych dysz chłodziwa do szlifowania zamka łopatki silnika lotniczego, wykonywanych techniką przyrostową

Projektowanie i analiza MES kształtowych dysz chłodziwa do szlifowania zamka łopatki silnika lotniczego, wykonywanych techniką przyrostową

Projekt i analiza MES dysz kształtowych chłodziwa do szlifowania zamka łopatki silnika lotniczego

Projekt i analiza MES dysz kształtowych chłodziwa do szlifowania zamka łopatki silnika lotniczego

Measurements of Hub Flow Interaction on Film Cooled Nozzle Guide Vane in Transonic Annular Cascade

An experimental study has been performed in a transonic annular sector cascade of nozzle guide vanes (NGVs) to investigate the aerodynamic performance and the interaction between hub film cooling and mainstream flow. The focus of the study is on the endwalls, specifically the interaction between the hub film cooling and the mainstream. Carbon dioxide (CO2) has been supplied to the coolant holes to serve as tracer gas. Measurements of CO2 concentration downstream of the vane trailing edge (TE) can be used to visualize the mixing of the coolant flow with the mainstream. Flow field measurements are performed in the downstream plane with a five-hole probe to characterize the aerodynamics in the vane. Results are presented for the fully cooled and partially cooled vane (only hub cooling) configurations. Data presented at the downstream plane include concentration contour, axial vorticity, velocity vectors, and yaw and pitch angles. From these investigations, secondary flow structures such as the horseshoe vortex, passage vortex, can be identified and show the cooling flow significantly impacts the secondary flow and downstream flow field. The results suggest that there is a region on the pressure side (PS) of the vane TE where the coolant concentrations are very low suggesting that the cooling air introduced at the platform upstream of the leading edge (LE) does not reach the PS endwall, potentially creating a local hotspot.

The Effect of Various Diameters Orifice Nozzle Coolant on Surface Roughness Performance in CNC Turning

This paper presents the effect of the diameter of orifice nozzle coolant on cutting performance of aluminum alloy 6066 in turning operations. The main factors affecting the performance and the major influence are tool wear, tool life, chip deformation and surface roughness by using coated cemented carbide Al2 O3 insert. The surface roughness and chip deformation performance of the various diameter of orifice nozzle and velocity of coolant on cutting is investigated. The experiments were carried out on 2 axes CNC lathe machine. The result revealed that the good performance of surface roughness at the smallest nozzle orifice size with velocity given a great influence on cutting speed performance.

Improved coolant supply through slotted grinding wheel

A suitable coolant supply in grinding is mandatory to comply with the demanded workpiece quality, to avoid thermal damage and to reduce tool wear. In this paper, the development of a slotted grinding wheel with optimized coolant supply is described. This simple but efficient approach was based on previous investigations on external and internal supply methods, which are briefly described. The performance of the slotted grinding wheel in comparison to two other grinding wheels, applying the same coolant nozzle for each, revealed significant improvements in the cooling efficiency.

DÉVELOPPEMENT D’UN MODÈLE SEMI-EMPIRIQUE POUR LA PRÉDICTION DE LA COHÉRENCE D’UN JET UTILISÉ DANS LES PROCÉDÉS DE RECTIFICATION

The productivity of Continuous Dress Creep Feed (CDCF) grinding processes is mainly limited by the burning marks that appear on the machined surfaces if too aggressive cutting parameters are selected. This issue can be solved by improving coolant application in the grinding zone by using coherent coolant nozzle. To study the effects of design parameters of a nozzle on the coherency of the cooling jet while diminishing costs and times related to an experimental approach, the present work demonstrates how to elaborate a semiempirical model that predicts the physical coherency of a water-based coolant jet produced by a Webster type nozzle using mainly computational fluid dynamic (CFD) results. In order to establish this semi-empirical model, a minimum of experimental results are required. The model uses the opening of the numerical velocity profiles to make the predictions. Our results demonstrate that the model developed, using our approach, can predict the physical coherency of the water-based coolant jet with less than 4% of error.

Development of CO2 gas cluster cleaning method and its characterization

As devices become smaller to the extent of nano-scale, dry damage-free cleaning process has become an important area of study. Gas cluster cleaning technology has a potential to remove contaminant particles from the surface of semiconductor wafers without damage because a gas cluster is smaller than 100 nm in diameter. In this paper, a new dry cleaning process using a CO2 gas cluster beam is developed and a characterization method for gas cluster generation was studied experimentally. First, a CO2 gas cluster cleaning system was built to evaluate the feasibility of cleaning by use of a gas cluster beam, which is generated by expansion of gas through a converging–diverging nozzle and nozzle chilling. Cleaning tests were performed several times. Twenty-five to three hundred nanometers silica particles were cleaned off from the surface of a bare Si wafer and of a wafer with 60 nm poly-silicon structure by using this cleaning system. Preliminary result showed that the contaminants were successfully removed without damage to the wafer surface. To characterize the gas cluster, we used the particle beam mass spectrometer (PBMS) for the measurement of the size distribution of the gas clusters. The size distribution of clusters is measured by varying flow rate and nozzle coolant temperature. From the measurement results, the size of a gas cluster was less than 40 nm, which is expected to cause no damage on a surface based on the measurement of pattern collapse force. By using the PBMS, CO2 gas cluster cleaning system can be optimized to provide the maximum cleaning efficiency for nano-scale contaminant particles without damage to substrate surfaces.

S1303-1-4 シャーベット噴流援用ワイヤ放電加工によるインコネル材の高能率加工([S1303-1]先端材料と加工(1))

This paper presents the high performance and cost effective machining method for difficult-to-cut material such as Inconel 718. The machining of engine components for aerospacial vehicle often requires a special machine tool: broach machine because of the high accuracy and limited tolerance for machined parts. Wire discharge machining is quite useful tool for cutting difficult-to-cut material, though the speed of machining is relatively low and, the ordinary processing chamber is not enough large to settle the big component of jet engine. In this study, to raise the cutting speed, hybrid coolant nozzles were developed, and the NC index machine were integrated into the small WDM machine. Thus the high performance machining with small WDM machine and the high speed cutting of Inconel 718 were realized.

A Material Model for the Lifetime Prediction of Regeneratively Cooled Nozzle Structures

AbstractRegeneratively cooled nozzle structures of a Reusable Launch Vehicle (RLV) belong to the most critical components of a space shuttle main engine. The severe operating conditions have been experimentally observed to cause the so‐called “dog‐house” failure mode. Within the DFG Project to develop new technologies for the future space transportation system, a material model which sufficiently describes this phenomenon is needed. In this project we are using a new continuum mechanical approach motivated by a rheological model. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Interactive fixture and tool space design considering tool movement, machine, and inspection for five-axis grinding

This paper proposes a novel method of collision-free fixture and tool space design for five-axis grinding, considering tool movement, machine degrees of freedom, the machine envelope, inspection, and related features. The fixture space is designed in three steps. First, the fixture space is generated as the remaining space after cutting out the tooling space (i.e. the sweeping space of the grinding wheel along the profile of the machined features). In this way, the fixture space is naturally collision-free with respect to tool movement. Second, the fixture space is further modified based on the constraints imposed by the grinding machine centre, which include over-travel distance, the positions of coolant nozzle and wheel dresser, and so on. Third, the fixture space is modified again according to measurements conducted by coordinate measuring machines and in-cycle machine probes. Interactions of fixture space with tool space, machine, and inspection are considered. The fixture space design for holding aerofoil blades on a five-axis machining centre Makino A55 for grinding operations is used as a case study, and the results of this study have been verified by computer-aided manufacture (CAM) simulation software Vericut and physical experiments using dummy wheels.