Prediction of Tool-Chip Interface Temperature in Cryogenic Machining of Ti–6Al–4V: Analytical Modeling and Sensitivity Analysis

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Sinan Kesriklioglu ◽  
Frank E. Pfefferkorn
Keyword(s):  
Heat Transfer ◽  
Sensitivity Analysis ◽  
Liquid Nitrogen ◽  
Flow Rate ◽  
Cutting Speed ◽  
Design Parameters ◽  
Interface Temperature ◽  
Cryogenic Machining ◽  
Cooling Strategy ◽  
Cutting Insert

Abstract The goal of this work is to predict the tool-chip interface temperature during cryogenic machining and determine the effectiveness of this cooling strategy. Knowledge of the tool-chip interface temperature is needed to conduct process planning: choosing a tool cooling geometry, cutting speed, and cryogen flow rate as well as predicting tool life and achievable material removal rate. A detailed explanation of the analytical heat transfer model is presented, which is a modified form of Loewen and Shaw's orthogonal cutting model, where a thermal resistance network is applied to represent the heat transfer mechanisms in, and out of, the cutting tool. An in-depth discussion of the temperature rise at the tool-chip interface during orthogonal machining of titanium alloy Ti–6Al–4V is presented. The effect of cutting speed, cryogen flow rate and quality, and cooling strategy are explored. The model is used to compare the effect of internal cryogenic cooling with external flood cooling using a water-based metalworking fluid or liquid nitrogen. A sensitivity analysis of the model is conducted and ranks the relative importance of various design parameters. The thermal conductivity of the cutting insert has the greatest influence on the predicted interface temperature. The low boiling temperature and phase change are what make internal cooling of a cutting insert with liquid nitrogen effective at reducing the tool-chip interface temperature. If the heat flowing into the tool, from the tool-chip interface, does not exceed the available latent heat in the cryogen, then this method is more effective than external flood cooling.

An Experimental Study on Cryogenic Spray Quenching of a Circular Metal Disk II. Chilldown Efficiency and Effects of Coating and Flow Pulsing

2021 ◽  
Author(s):  
Jun Dong ◽  
Hao Wang ◽  
Samuel Darr ◽  
Jason Hartwig ◽  
Jacob Chung
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Liquid Nitrogen ◽  
Mass Flow ◽  
Flow Rate ◽  
Continuous Flow ◽  
Nucleate Boiling ◽  
Film Boiling ◽  
Teflon Coating ◽  
Bare Surface

Abstract This is the second part of a two-part series that presents the results of liquid nitrogen spray quenching of a Stainless Steel disc. The results of continuous-flow spray chilldown of a bare surface disc are summarized first that serves as the baseline information for evaluating the effects of disc surface coating and pulse flow. We found that for continuous-flow spray chilldown of a bare surface disc, the chilldown efficiency is mainly a function of the average mass flow rate with the trend of decreasing efficiency with increasing mass flow rate. Additional experiments were performed to evaluate the enhancement of cryogenic spray quenching by three techniques: 1. Using intermittent pulse sprays on SS bare surface, 2. Coating the SS surface with a layer of low thermal conductivity Teflon film, and 3. Spraying liquid nitrogen intermittently on the coated SS surface. In general, the results indicate that all three methods effectively produced higher spray thermal efficiencies and reduced liquid nitrogen mass consumption. However, it was also found that the Teflon coating was more effective than the flow pulsing due to that the Teflon coating induced a large surface temperature drop at the beginning of the chilldown that allowed the quenching to move quickly from poor heat transfer film boiling to efficient heat transfer transition and nucleate boiling regimes. This quick transition shortens the film boiling period, thus facilitates the switch to much higher heat transfer transition boiling and nucleate boiling periods earlier to complete the chilldown process faster.

Research on surface heat transfer mechanism of liquid nitrogen jet cooling in cryogenic machining

2020 ◽  
Vol 179 ◽  
pp. 115607
Author(s):  
Yongqing Wang ◽  
Minghua Dai ◽  
Kuo Liu ◽  
Jiaxin Liu ◽  
Lingsheng Han ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Liquid Nitrogen ◽  
Surface Heat ◽  
Transfer Mechanism ◽  
Heat Transfer Mechanism ◽  
Cryogenic Machining ◽  
Surface Heat Transfer ◽  
Jet Cooling

scholarly journals RESEARCH OF THE FUNCTIONING AND OPTIMIZATION PROCESS OF THE STRUCTURAL-TECHNOLOGICAL PARAMETERS

2020 ◽  
pp. 142-150
Author(s):  
Vitaliy Yaropud
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flow Rate ◽  
Thermal Power ◽  
Design Parameters ◽  
Theoretical Studies ◽  
Technological Parameters ◽  
Air Flows ◽  
Counter Current ◽  
Pipe Heat

Domestic and foreign scientists in recent years have performed a considerable amount of scientific research on the biological justification of optimal combinations of microclimate parameters required for the normal development of animals. However, the results of the studies do not allow one to specify the optimal parameters for different species of animals, taking into account their age, sex, weight and level of feeding. While it is possible to specify rather wide limits of change of temperature and relative humidity of air at which productivity is maximum, and technical and economic efficiency is approximately the same. Providing microclimate regulations in livestock premises is associated with significant costs of electricity and heat, which is about 17% of the producers' costs. To create a microclimate in livestock premises based on the above technological parameters and the analysis of the design features of the recuperators, two design and technological schemes of the three-pipe recuperator, which differ in the directions of movement of air flows, are proposed. The purpose of the research is to increase the efficiency of the technological process of functioning of the three-pipe recuperator for livestock premises by substantiating its structural and mode parameters. The results of theoretical studies of pneumatic losses in the three-pipe recuperator determined the dependence of pressure and power losses on the length of the air duct of the three-pipe recuperator, the radius of the external duct and the volume flow rate of air. As a result of theoretical studies, a mathematical model of the heat transfer process in a three-pipe heat exchanger was developed, with condensation in it, which allows to determine the temperature distribution of air flows by its length and its thermal capacity. The results of theoretical studies of the process of heat transfer in the design and technological schemes of a three-pipe recirculator with counter-current and direct-current showed that the counter-current variant is more effective. Optimization of the results of theoretical studies allowed us to determine the dependence of the design parameters of the three-pipe heat exchanger on the volumetric flow rate of air, subject to the highest useful thermal power.

Optimal Design of Heat Transfer and Fluid Flow Using Adjoint Sensitivity Analysis

2007 ◽  
Author(s):  
Kazunari Momose ◽  
Kaoru Ikejima ◽  
Hideshi Ishida ◽  
Genta Kawahara
Keyword(s):  
Heat Transfer ◽  
Sensitivity Analysis ◽  
Fluid Flow ◽  
Boundary Conditions ◽  
Descent Method ◽  
Steepest Descent Method ◽  
Design Parameters ◽  
Adjoint Sensitivity Analysis ◽  
Adjoint Sensitivity ◽  
Thermal Boundary Conditions

An optimization system based on adjoint sensitivity analysis has been developed for heat transfer and fluid flow design, the objective of which is, for example, the maximization of local temperature or to achieve the target temperature distributions in specific regions by controlling the flow and thermal boundary conditions as the design parameters. Using the system, the sensitivities on whole boundary can be obtained by a couple of numerical computations of the conventional forward problem and the corresponding adjoint problem. Moreover, by combining with a commercial CFD software as a front end and with the steepest descent method as an optimizer, we show that the flow and thermal boundary conditions can automatically be optimized.

Flow and Heat Transfer Analysis of an Electro-Osmotic Flow Micropump for Chip Cooling

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
K. Pramod ◽  
A. K. Sen
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Analytical Model ◽  
Flow Rate ◽  
Maximum Flow ◽  
Back Pressure ◽  
Design Parameters ◽  
Chip Cooling ◽  
Flow And Heat Transfer ◽  
Electro Osmotic Flow

This paper reports theoretical and numerical analysis of fluid flow and heat transfer in a cascade electro-osmotic flow (EOF) micropump for chip cooling. A simple analytical model is developed to determine the temperature distribution in a two-dimensional (2D) single channel EOF micropump with forced convection due to a voltage difference between both ends. Numerical simulations are performed to determine the temperature distribution in the domain which is compared with that predicted by the model. A novel cascade EOF micropump with multiple microchannels in series and parallel and with an array of interdigitated electrodes along the flow direction is proposed. The simulations predict the maximum flow rate and pressure capability of one single stage of the micropump and the analytical model employs equivalent circuit theory to predict the total flow rate and back pressure. Each stage of the proposed micropump comprises sump and pump regions having opposing electric field directions. The various design parameters of the micropump includes the height of the pump and sump (h), number of stages (n), channel width (w), thickness of the channel wall or fin (r), and width ratio of the pump and sump (s:p) regions. Numerical simulations are performed to predict the effects of these design parameters on the pump performance which is compared with that predicted by the analytical model. The micropump is used for cooling cooling of an Intel® CoreTM i5 chip which produces a maximum heat of 95 W over an area of 3.75 × 3.75 cm. Based on the parametric studies a design for the cascade EOF micropump is proposed which provides a maximum flow rate of 14.16 ml/min and a maximum back pressure of 572.5 Pa to maintain a maximum chip temperature of 310.63 K.

Experimental Investigation of an Ultrathin Manifold Microchannel Heat Sink for Liquid-Cooled Chips

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
W. Escher ◽  
T. Brunschwiler ◽  
B. Michel ◽  
D. Poulikakos
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Flow Rate ◽  
Heat Sink ◽  
Volumetric Flow Rate ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Cooling Power ◽  
Microchannel Heat Sink ◽  
Manifold Microchannel

We report an experimental investigation of a novel, high performance ultrathin manifold microchannel heat sink. The heat sink consists of impinging liquid slot-jets on a structured surface fed with liquid coolant by an overlying two-dimensional manifold. We developed a fabrication and packaging procedure to manufacture prototypes by means of standard microprocessing. A closed fluid loop for precise hydrodynamic and thermal characterization of six different test vehicles was built. We studied the influence of the number of manifold systems, the width of the heat transfer microchannels, the volumetric flow rate, and the pumping power on the hydrodynamic and thermal performance of the heat sink. A design with 12.5 manifold systems and 25 μm wide microchannels as the heat transfer structure provided the optimum choice of design parameters. For a volumetric flow rate of 1.3 l/min we demonstrated a total thermal resistance between the maximum heater temperature and fluid inlet temperature of 0.09 cm2 K/W with a pressure drop of 0.22 bar on a 2×2 cm2 chip. This allows for cooling power densities of more than 700 W/cm2 for a maximum temperature difference between the chip and the fluid inlet of 65 K. The total height of the heat sink did not exceed 2 mm, and includes a 500 μm thick thermal test chip structured by 300 μm deep microchannels for heat transfer. Furthermore, we discuss the influence of elevated fluid inlet temperatures, allowing possible reuse of the thermal energy, and demonstrate an enhancement of the heat sink cooling efficiency of more than 40% for a temperature rise of 50 K.

Study of Heat Transfer Characteristics and Kerf Quality of Flame Jet Cutting

2014 ◽  
Vol 931-932 ◽  
pp. 392-396
Author(s):  
Chayut Nuntadusit ◽  
Prapas Muangjunburee ◽  
Nattaphum Suwanmala ◽  
Makatar Wae-Hayee
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Flow Rate ◽  
Transfer Rate ◽  
Steel Plate ◽  
Cutting Speed ◽  
Pure Oxygen ◽  
Heat Flux Sensor ◽  
Impingement Surface

The aim of this research is to study heat transfer rate of impinging flame jet and cutting quality of steel plate using flame jet. The cutting torch was used for heating on the impingement surface, and it was used for cutting the steel plate samples. LPG at constant flow rate of 0.14 kg/s was mixed with pure oxygen at varied flow rate corresponding to equivalence ratio, =0.78, 0.93 and 1.16. The nozzle-to-plate distance was examined at h=3, 4, 5, 6, 7 and 8 mm. Heat transfer rate on the impingement surface was measured using water cooled heat flux sensor. In order to investigate cutting quality, steel plate with 6 mm in thickness was cut by this flame jet with cutting speed at 260 mm/min. The surface roughness, slag quantity and kerf characteristics were considered for cutting quality. The results show that the flame jet for condition of =0.78 at h=4 mm gives the highest heat transfer rate. The flame jet for condition of =0.93 at h=6 mm is optimal for using cutting steel plate in this study.

The Sensitivity Analysis of Wellbore Heat Transfer during the CO2 Injection Process

2014 ◽  
Vol 889-890 ◽  
pp. 1638-1643
Author(s):  
Yi Zhang ◽  
Tong Tong Li ◽  
Yong Chen Song ◽  
Duo Li ◽  
Yang Chun Zhan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Sensitivity Analysis ◽  
Flow Rate ◽  
Injection Pressure ◽  
Simulation Method ◽  
Injection Process ◽  
Injection Flow ◽  
Injection Temperature ◽  
Thomson Coefficient

The sensitivity analysis of wellbore heat transfer during the CO2injection process is of vital importance to Carbon dioxide utilization and sequestration (CCUS). A numerical simulation method is developed to simulate the process of wellbore heat transfer during injecting carbon dioxide by amending the classical heat transfer modelRamey models. It analyses how the selected parameters affect the distribution of the wellbore temperature and pressure, which include CO2injection temperature, pressure and density, the injection flow rate and Joule Thomson coefficient. The results show that, CO2injection temperature has greater impact on the initial level of the temperature distribution; higher injection pressure raises the temperature mainly because of the effect of Joule Thomson coefficient; also, when the injection process lasts a longer time, the distribution is much more stable. When the injection flow rate is higher, the strata temperature has less influence on the flow temperature. The injection pressure and density has very appreciable effect on the pressure distribution. However, the other parameters have less influence on it. The modified simulation method was applied in Jiangsu Caoshe oil field and the simulation results coincided with the measuring data well.

Characterization of Tool–Chip Interface Temperature Measurement With Thermocouple Fabricated Directly on the Rake Face

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Sinan Kesriklioglu ◽  
Cory Arthur ◽  
Justin D. Morrow ◽  
Frank E. Pfefferkorn
Keyword(s):  
Temperature Measurement ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Smart Manufacturing ◽  
Future Research ◽  
Interface Temperature ◽  
Rake Face ◽  
Serrated Chip ◽  
Cutting Insert

The objective of this work is to fabricate thermocouples directly on the rake face of a commercially available tungsten carbide cutting insert for accurately measuring the tool–chip interface temperature during metal cutting. The thermocouples are sputtered onto the cutting insert using micromachined stencils, are electrically isolated with layers of Al2O3, and receive a top coating of AlTiN for durability. The result is a nonsacrificial thermocouple junction that is approximately 1.3 µm below the rake face of the tool and 30 µm from the cutting edge. Experimental and numerical characterization of the temperature measurement accuracy and response time are presented. The instrumented cutting tool can capture the tool–chip interface temperature transients at frequencies of up to 1 MHz, which enables the observation of serrated chip formation and adiabatic shear events. Temperature measurements from oblique machining of 4140 steel are presented and compared with three-dimensional, transient numerical simulations using finite element analysis, where cutting speed and feed are varied. This method of measuring the tool–chip interface temperature shows promise for future research and smart manufacturing applications.

Sensitivity Analysis of a Heat Exchanger Tube Fitted With Cross-Cut Twisted Tape With Alternate Axis

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
M. E. Nakhchi ◽  
J. A. Esfahani
Keyword(s):  
Heat Transfer ◽  
Sensitivity Analysis ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Diameter Ratio ◽  
Design Parameters ◽  
Twisted Tape ◽  
Heat Exchanger Tube ◽  
Exchanger Tube

Numerical simulations are used to analyze the thermal performance of turbulent flow inside heat exchanger tube fitted with cross-cut twisted tape with alternate axis (CCTA). The design parameters include the Reynolds number (5000<Re<15,000), cross-cut width ratio (0.7<b/D<0.9), cross-cut length ratio (2<s/D<2.5), and twist ratio (2<y/D<4). The objective functions are the Nusselt number ratio (Nu/Nus), the friction factor ratio (f/fs), and the thermal performance (η). Response surface method (RSM) is used to construct second-order polynomial correlations as functions of design parameters. The regression analysis shows that heat transfer ratio decreased with increasing both the Reynolds number and the width to diameter ratio of the twisted tape. This means that the twisted tape has more influence on heat transfer at smaller inlet fluid velocities. Sensitivity analysis reveals that among the effective input parameters, the sensitivity of Nu/Nus to the Reynolds number is the highest. The results reveal that thermal performance enhances with increasing the width to diameter ratio of the twisted tape (b/D). The maximum thermal performance factor of 1.531 is obtained for the case of Re=5000, b/D=0.9, s/D=2.5, and y/D=4.

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