High Pressure Coolant Research Articles

Optimizing Power Consumption in Machining Nickel-Based Superalloys: Strategies for Energy Efficiency

<div>In the face of the world’s population growth and ensuing demands, the industrial sector assumes a crucial role in the management of limited energy supplies. Superalloys based on nickel, which are well-known for their remarkable mechanical qualities and resilience to corrosion, are now essential in vital applications like rocket engines, gas turbines, and aviation. However, these metals’ toughness presents a number of difficulties during machining operations, especially with regard to power consumption. This abstract explores the variables that affect power consumption during the machining of superalloys based on nickel in great detail and suggests ways to improve energy efficiency in this area. The effects of important variables on power consumption are extensively investigated, including cutting speed, feed rate, depth of cut, tool geometry, and cooling/lubrication techniques. A careful balance between these factors is necessary to maximize machining efficiency and reduce power usage. Furthermore, this study reviews the effect of different heat source applications on power consumption and the resultant quality of machined nickel-based superalloys. Additionally, the critical role of cooling and lubrication in mitigating the adverse effects of high temperatures generated during machining is thoroughly examined. Innovative cooling strategies, including cryogenic or high-pressure coolant systems, are explored as potential avenues to enhance heat dissipation and minimize power requirements. In essence, this abstract not only sheds light on the challenges inherent in machining nickel-based superalloys but also offers actionable insights into how energy efficiency can be maximized through strategic parameter optimization and the adoption of innovative cooling techniques. By addressing these aspects, manufacturers can effectively navigate the complexities of machining superalloys while minimizing their environmental footprint and operational costs.</div>

Boiling of Coolant Near the Cutting Edge in High Speed Machining of Difficult-to-Cut Materials

This study investigates film boiling of coolant as a cooling inhibitor in a narrow wedge-shaped space between the tool flank face and the machined surface of a workpiece, observed during high-speed turning of stainless steel SUS304 and nickel-based superalloy Inconel 718. The boiling, likely triggered by high surface temperatures at both the face and surface close to the cutting edge, impedes coolant access to the tool tip area and efficient cooling. Therefore, the impact of coolant pressure on the boiling zone size was initially explored across pressures ranging from 0.1 to 20 MPa. A burn mark band due to coolant boiling, distinctly visible on the flank face of an insert with a yellow hard coating, expanded over cutting time. The film boiling area width, or the distance from the flank wear area to the band, decreased with increasing coolant pressure, reflecting the enhanced cooling ability and tool life with high-pressure coolant. Applying Boyle–Charles’ law to film boiling indicated that vapor pressure was directly related to coolant velocity rather than pressure. In contrast, the boiling area width increased with increasing cutting speed.

Investigation of the Titanium Alloy Turning Process with Prime A Tools under High-Pressure Cooling Conditions

When turning titanium alloys, it is difficult to ensure the required quality with maximum machining efficiency. A typical problem in the turning process of titanium alloys is to achieve effective breaking and removal of chips from the machining zone. The combination of the new construction of cutting tools and machining methods in the machining of titanium alloys increases the efficiency of the machining. For this reason, the use of tools typical for the Prime Turning method in combination with the high-pressure cooling (HPC) method was analysed. The longitudinal turning of the Ti6Al4V ELI titanium alloy was performed using Sandvik Coromant grade 1115 carbide tools. An increase in the pressure of the cutting fluid to p = 70 bar was used. Measurements of the components of the total cutting force for finishing machining with variable cutting parameters in the range of: feed rates f = <0.1;0.4> mm/rev, cutting depth ap = <0.25;1.0> mm and cutting speed vc = <40;80> m/min were performed. It has been shown that the values of cutting force are mainly dependent on the feed and the depth of cut. An analysis of the forms of chips obtained is presented. The dependence of the applied cutting parameters on the value of the chip breakage coefficient Cch was determined. The method of searching for the maximum efficiency of the turning process was determined, taking into account the desired value of the chip breakage coefficient.

Hydrogen distribution in a BWŔs RPV and Mark II drywell during the progression of a severe accident with and without emergency coolant injection

This study is directed to determine potential risks associated to hydrogen concentrations in an originally fully inertized drywell of a BWR Mark II primary containment, as a consequence of the progression of a severe accident. An unmitigated case and a case with partial recovery of emergency coolant injection are studied. The base case accident scenario to determine hydrogen in-core generation and release rates to drywell is the Large Break Loss-of-Coolant Accident of a BWR, occurring simultaneously with a total loss of power. Two alternative scenarios are simulated by allowing the recovery of the High Pressure Coolant System during the progression of the base case scenario. The code RELAP/SCDAPSIM is used to simulate the different stages in the accident scenarios, and the code GASFLOW was used to compute the hydrogen distribution in a fully pre-inertized drywell. Results of hydrogen and fission product generation in core, as well as state of core degradation are presented. Then, a comparison of results of hydrogen concentration in drywell between the base case and the cases with coolant injection are presented. Results show that, for the base case, by the time of reaching primary containment venting pressure setpoint, the drywell upper zone reaches about 9 % of hydrogen concentration. For the other two cases, the resulting peak hydrogen concentrations were 12 % and 15 %.

Investigation of the Cutting Fluid Incidence Angle Direction in Turning Grade 5 ELI Titanium Alloy under High-Pressure Cooling Conditions.

The use of high-pressure cooling (HPC) in machining can increase the efficiency and improve process stability through more effective breaking and chip evacuation. Turning tests of the Grade 5 ELI titanium alloy were carried out using cemented carbide tools and taking into account the direction of feeding of the cutting liquid. Measurements of the components of the total cutting force were carried out for feeds in the range f = <0.08; 0.13> mm/rev and two angular settings (i.e., angle α = <30°; 90°> and β = <0°; 60°>) of the nozzle. The chip breakage coefficient was determined. It was shown that the cutting force values depended on the feed value, and the angle of feeding of the cutting fluid did not significantly affect the values of the cutting forces. Despite the different forms of chips obtained, the applied method of searching for the best conditions was unsuccessful and no significant effect on the values of the chip breaking coefficient Cch was observed. To determine the best nozzle setting, it is useful to determine the working area of the chip breaker. Due to the shape of the chip, the optimal angular setting for the nozzle that supplied the cutting fluid was α = 60° and β = 30°. In addition, it was observed that the angle of incidence of the cutting fluid jet could affect the chip formation process and support the chip cracking process.

Prediction of stress-fatigue life on the impeller of the reactor coolant pump based on fluid-thermal-structure interaction method

The reactor coolant pump (RCP) is the core part of the first loop in nuclear power plant. It plays a crucial role on the stability and security of the nuclear reactor operation. As the only rotating equipment in the RCP, the impeller needs to run tens of thousands of cycles in the high-temperature and high-pressure coolant, which significantly affects the physical properties and reduces the fatigue life. This paper mainly studies the law of the dynamic stress on impeller of the RCP based on the fluid-thermal-structure interaction method, further predicting the stress-fatigue life of the impeller based on the Palmgren-Miner theory. The results show that the impeller is subjected to periodic alternating stress during rotation. The stress value gradually increases with the increase of the flow. The location and value of the maximum stress on the impeller at each moment are inconsistent. The highest negative correlation between the stress amplitude and the fatigue life is found, and the correlation is more than 19%. Fatigue failure first occurs at the junction between the inlet edge of the blade and the hub, and the fatigue life on the impeller is calculated to be 146.6 years. The fatigue life of the impeller is greater than the designed life, thus characterizing the impeller safe for use in nuclear power plant.

Comparative evaluation and sensitivity analysis of multi-modelling and optimization of milling Ti–6Al–4V alloy with high-pressure coolant jets

An effective cooling method with the proper selection of process parameters can intensify the machining performance by reducing the loss of resources with better quality products. In this regard, modelling is an appropriate way of predicting responses in changing environment and optimization is an efficient tool of selecting the best process parameters based on the specific desire. With a view to enhance the machinability of Ti–6Al–4V alloy, the first attempt of the current study was to predict the performance characteristics of milling such as cutting force (N), specific cutting energy (J/mm3) and surface roughness (μm) with the variation of speed (m/min), feed (mm/min), depth of cut (mm) and cooling approach by developing mathematical models. For the present work, three different predictive models such as response surface methodology (RSM), artificial neural network (ANN), and adaptive neuro fuzzy inference system (ANFIS) was followed. Additionally, a comparative assessment of the used predictive models was carried out and ANFIS was noticed as the most accurate predictive model. After that, optimization of the selected responses was conducted by multiple-objective optimization on the basis of ratio analysis (MOORA) method where the relative weights of each response were defined by principal component analysis (PCA). For milling Ti–6Al–4V alloy within the specific boundary conditions, PCA-MOORA suggested an optimal parameter setting at 32 m/min speed, 22 mm/min feed rate, and 0.75 mm depth of cut with rotary high-pressure cooling. Finally, the sensitivity of the used MOORA method with the variation of unitary ratio was checked out to take a robust decision.

An analysis of different cutting strategies to improve tool life when machining Ti-5Al-5V-5Mo-3Cr alloy

Ti-5Al-5V-5Mo-3Cr is a near-beta titanium alloy generally employed in the production of high strength parts. Its high tensile strength and light weight, compared to Ti-6Al-4V, make it a suitable choice for landing gear parts and advanced structural components. However, due to its high strength-to-weight ratio, mechanical strength at elevated temperatures, and oxidation resistance, the cutting zone experiences high cutting temperatures, which, combined with a low rate of heat transfer during the machining process, consequently, generates stress, causing premature tool failure. In this paper, several distinct experimental approaches were applied, different machining condition combinations (tools and coolants) were compared, cutting tool wear performance was diagnosed, and, finally, optimized cutting parameters were identified. The main objective of this research was to understand how these parameters affect tribological behavior when machining Ti-5Al-5V-5Mo-3Cr. One of the PCD tools possessed the longest life under high pressure coolant of 28 %–170 % longer than the other tool materials. The main wear mechanism was a combined abrasion, adhesion/attrition, diffusion, and oxidation. Optimizing cooling conditions can affect cutting forces substantially, minimizing residual stress, improving the surface roughness, and reducing the work-hardening during machining. Therefore, the results show that the combination of coolant and cutting tool material leads to longer tool life and improved surface integrity.

Effects of high-pressure coolant on cooling mechanism in high-speed ultrasonic vibration cutting interfaces

Cutting temperature can be effectively reduced by high-pressure coolant (HPC) method. When using HPC on high-speed ultrasonic vibration cutting (HUVC), the precision machining cutting speed on titanium alloys could reach to 400 m/min due to the significant cutting temperature reduction resulted from HPC and ultrasonic vibration. However, when the cutting speed continued to increase, the advantages of HUVC with HPC were vanished rapidly. Therefore, it was necessary to figure out the effect of HPC on the cooling mechanism of HUVC for further improvement in high-speed machining. In this paper, computational fluid dynamics (CFD) method and experiments on tool life were applied. The results demonstrated that even though the effect of ultrasonic vibration (Nusselt Number) was reduced sharply by HPC from 158,368 to 78296, the high coolant inlet velocity and large temperature gradient caused by the thinned stable-thermal boundary layer (S-TBL) in the cases of applied HPC would in one side cover the loss of the benefits of ultrasonic vibration and in the other side furtherly enhance the heat transfer ability from 26,158 to 46830 J/m2 s. Thus, the tool life had been significantly prolongated more than 10 times. After revealing the cooling mechanism from the aspect of HPC transient state within ultrasonic vibration interfaces, the theory foundation of how to further improve the machinability of difficult-to-cut materials by HUVC was developed.

Performance evaluation of high-pressure cooling by using external rotary liquid applicator in milling Ti–6Al–4V alloy

An effective cooling mode with appropriate process parameters can enhance the machinability as well as productivity. In this regard, this study focuses on evaluating the machinability of widely used Ti–6Al–4V alloy with the use of high-pressure coolant jets compared to dry milling. A novel rotary applicator was designed and developed to feed high-pressure coolant jets without any drastic change of solid end mill cutter. Four flutes solid HSS end mill cutter was selected for machining because of its some intensive properties. Biodegradable VG-68 cutting oil was chosen as cutting fluid due to its better thermo-physical properties with higher flash points. Machinability was assessed at 16–32 m/min cutting speeds and feed rates of 0.08–0.16 mm/tooth with a constant depth of cut of 1.0 mm, taking into account the average cutting temperature, resultant cutting force, mean surface roughness, and tool wear. Dry milling produced the worst results for all of the investigated responses, with excessive tool wear due to the lack of cooling and lubrication. Compared to dry milling, high-pressure cooling (HPC) lowered average cutting temperature, resultant cutting force, and mean surface roughness by 11.21–21.57%, 8.63–13.12%, and 6.09–29.6%, respectively, whereas rotary high-pressure cooling (RHPC) reduced these parameters by 15.39–27.27%, 14.05–21.18%, 16.48–41.04%. RHPC's efficient cooling and lubrication increased the machinability of the Ti–6Al–4V alloy. Dry milling showed severe flank wear with increased built-up edge (BUE) development, abrasion, and adhesion, whereas HPC and RHPC dramatically reduced the severity of tool wear. In HPC and RHPC, the tool life was consequently increased by 6.8 and 9 min, respectively.

Wear resistance enhancement of Inconel 718 via high-speed ultrasonic vibration cutting and associated surface integrity evaluation under high-pressure coolant supply

Machining-induced surface integrity evaluation and functional performance are considered as the most representative problems for evaluating the machining quality of Ni-based superalloys (for example, Inconel 718). Although high-speed ultrasonic vibration cutting (HUVC) has been proved to be effective for improving the machinability of Inconel 718, the surface integrity and its effect on functional performance (for example, wear resistance) are still unclear. By applying scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and white light interferometry (WLI), the surface integrity induced by HUVC and the wear resistance of the machined surface were comprehensively evaluated; the grain refinement, hardness increase, and wear mechanism of the machined surface were thoroughly studied, which were compared with the conventional cutting (CC) process. Compared with the CC process, the HUVC process achieves superior grain refinement, thicker surface plastic deformation layer, lower surface roughness Ra and Rz, higher hardness and compressive residual stress, and thicker hardening layer. The wear rate of the machined surface processed by HUVC is reduced by at most 24.01%. This study shows that the HUVC process can be potentially used to improve the wear resistance, which can effectively achieve grain refinement, surface roughness reduction, and wear resistance improvement while reducing the machining cost and process procedure.

Research on Cutting Layer Characteristics of Superalloy under High-Pressure Cooling.

Superalloys are widely used in the aerospace field and are a typical difficult-to-cut material. When the PCBN tool is used to cut superalloys, there will be problems such as a large cutting force, a high cutting temperature, and gradual tool wear. High-pressure cooling technology can effectively solve these problems. Therefore, this paper carried out an experimental study of a PCBN tool cutting superalloys under high-pressure cooling and analyzed the influence of high-pressure coolant on the characteristics of the cutting layer. The results show that the main cutting force can be reduced by 19~45% and 11~39% when cutting superalloys under high-pressure cooling compared with dry cutting and atmospheric pressure cutting, respectively, in the range of test parameters. The surface roughness of the machined workpiece is less affected by the high-pressure coolant, but the high-pressure coolant can help reduce the surface residual stress. The high-pressure coolant can effectively improve the chip's breaking ability. In order to ensure the service life of PCBN tools, when cutting superalloys under high-pressure cooling the coolant pressure should not be too high, and 50 bar is more appropriate. This provides a certain technical basis for the efficient cutting of superalloys under high-pressure cooling conditions.

Influence of Flank Wear on the Microstructure Characteristics of the GH4169 Metamorphic Layer under High-Pressure Cooling.

Since the flank has an important influence on the surface of a workpiece, and as microstructure flaws of the surface metamorphic layer are a key factor that affects the service performance of a part, this work studied the influence of flank wear on the microstructure characteristics of the metamorphic layer under the conditions of high-pressure cooling. First, Third Wave AdvantEdge was used to create a simulation model of cutting GH4169 using tools with different flank wears under high-pressure cooling. The simulation findings emphasized the impact of flank wear width (VB) on the cutting force, cutting temperature, plastic strain, and strain rate. Second, an experimental platform was established for cutting GH4169 under high-pressure cooling, and the cutting force during the machining process was recorded in real time and compared with the simulation results. Finally, an optical microscope was used to observe the metallographic structure of the GH4169 workpiece section. The microstructure characteristics of the workpiece were analyzed using a scanning electron microscope (SEM) and electron backscattered diffraction (EBSD). It was discovered that, as the flank wear width increased, so did the cutting force, cutting temperature, plastic strain, strain rate, and plastic deformation depth. The relative error between the simulation results of the cutting force and the experimental results was within 15%. At the same time, near the surface of the workpiece, there was a metamorphic layer with fuzzy grain boundaries and refined grain. With an increase in flank wear width, the thickness of the metamorphic layer increased from 4.5 μm to 8.7 μm and the grain refinement intensified. The high strain rate promoted recrystallization, which caused an increase in the average grain boundary misorientation and high-angle grain boundaries, as well as a reduction in twin boundaries.

RSM design-based hybrid approach to multi-response optimization in milling Ti-6Al-4 V alloy: A comparative study

The Selection of appropriate process parameters in milling Ti-6Al-4 V alloy to reduce energy and power consumption while maintaining product quality and process stability is challenging. This study aims to optimize process parameters in milling Ti-6Al-4 V alloy with five primary criteria i.e., average cutting force, shear stress, specific cutting energy, power consumption, and average surface roughness. A total of 26 experimental tests was carried out with the variation of process parameters such as cutting speed (m/min), feed rate (mm/min), and depth of cut (mm) based on the Box-Behnken design (BBD) matrix of response surface method (RSM) under dry and high-pressure cooling (HPC). The criteria importance through the inter-criteria correlation (CRITIC) method was used to determine the relative weights of each response. At the same time, the evaluation of optimum process parameters was done by hybrid multi-response optimization (MRO) techniques such as complex proportional assessment (CRITIC-COPRAS), additive ratio assessment (CRITIC-ARAS), combined compromise solution (CRITIC-COCOSO) and technique for order of preference by similarity to ideal solutions (CRITIC-TOPSIS). After the evaluation, a cutting speed of 32 m/min, feed rate of 22 mm/min, and 0.75 mm depth of cut with HPC were selected as the optimum process parameters. Due to the lack of an identical solution, the sensitivity of the used MRO methods was checked out with the weight variation of the selected criteria. TOPSIS was noticed as the most robust MRO method with less sensitivity. Spearman’s Correlation coefficient was used to assess the correlation among the used hybrid MRO methods.

Role of CO2 cooling strategies in managing tool wear during the shoulder milling of grade 2 commercially pure titanium

As a result of their high hardness, osseointegration and low chemical reactivity titanium alloys have become an invaluable material species for use in medical applications. Unfortunately, many of the material properties which make titanium alloys desirable biomedical materials, also contribute towards difficulties in tool wear and surface quality during machining. Historically, this has been met via the application of robust metalworking fluid (MWF) strategies, e.g. flood, or high-pressure (HP) soluble oil coolant (emulsion). However, this brings with it its own challenges, not least of which the problem of coolant residue contamination. This study describes efforts to minimise and characterise tool wear during the shoulder milling of grade 2 commercially pure titanium (CP–Ti) by using a novel external supercritical CO2 (scCO2) coolant strategy. Whilst the results imply that the sole use of scCO2 coolant contributes to increased tool wear (relative to emulsion), an optimised strategy of combining scCO2 with minimum quantity lubrication (MQL) is shown to support up to a 245% increase in tool life. Despite this, machinability outcomes are found to be highly contingent upon proper selection of trial process variables such as scCO2 mass flow rate and cutting speed, wherein cutting speeds at or below 115 m/min, and 35 kg/h of scCO2 is generally shown to be the most efficacious parameters for this material/operation. Ultimately, scCO2 + MQL is found to be an effective compromise between the cleanliness of scCO2 and the improved function of emulsion.

Advancements in cooling techniques and its impact on machining: A review

During any machining process, a huge amount of heat is produced at the cutting zone which aggravates the tool wear. Tool cost is one of the prime concerns during machining. To increase the tool life, the heat produced during machining has to be removed effectively. In the past few decades various new concepts have been developed effectively to remove the heat from the cutting zone so that the tool life increases. In this article various methods that are in use and the recent developments in the field of cooling during different machining operations have been discussed. The various cooling methods like dry machining (natural cooling), air-cooling, flood, cryogenic, MQL cooling, high pressure coolant, solid lubricants and mist cooling are discussed along with their advantages and limitations and the recent advancements in each cooling method. Each cooling process has its own advantages and application area. It is concluded that dry machining is best for environment, MQL is nearer to dry machining with better machinability results and consumes very less lubricants, cryogenic cooling has very less impact on environment, high pressure coolant is better for specific target area and solid lubricants are good for high speed with high temperature. This article will help researchers to understand the methods and to find the best cooling and lubrication method to be adopted in industry with less impact on environment. One can easily find various research gaps which will help researchers to proceed further in this area.

Yakın Beta Ti Alaşımı, Ti-5553'ün Yüksek Basınçlı Soğutma ve Yağlama Altında İşlenmesinde Kalıntı Gerilme Analizi

Ti-5553 (Ti–5Al–5Mo–5V–3Cr) one of the titanium alloys, is a recently developed near beta Titanium alloy, which is frequently used in the aerospace industry such as landing gear. When machining these superalloys, surface integrity can be affected by cutting and cooling conditions. An experimental study was conducted on Ti-5553, also known as beta-like titanium alloy, to understand the role of High Pressure Cooling and Lubrication conditions on surface integrity. In this study, high pressure coolant levels and other machining parameters (cutting speed, feed rate) were chosen as variable factors. These various levels were selected in different values and used in the tests to emphasize the relations of the accepted shear conditions from the effective data in the formation of residual stresses, which is also a parameter of the surface integrity. The results demonstrate the need to prepare coolant pressure levels to improve work surface integrity in such a material. In order to reveal the consistency of the coolant pressure values with other determined cutting parameters and the accuracy of choice, a relationship optimization has been tried to be explained.

Turning of titanium alloy with PCD tool and high-pressure cooling

Titanium alloys are difficult to cut materials due to their low thermal conductivity, which leads to intensive tool wear. The general issue is finding the best combination of cutting tool material and cutting conditions to achieve high productivity. This study used PCD cutting tool material in combination with high-pressure cooling (HPC). The main task was to find the most suitable HPC mode (various HPC settings on the rake and flank faces of the cutting tool) and intensity to reduce tool wear at a high cutting speed. Tool wear, chips, and forces were measured, and surface quality was evaluated to gain an understanding of the machining process under these particular conditions. An ANOVA test was used to determine the significance of control factors such as tool life and HPC mode and intensity. The most suitable cutting speed was 300 m/min, where a limit spiral cutting length (SCL) of 3000 m was achieved. Setting the HPC mode revealed the necessity of using the HPC on the rake face. However, the HPC on the flank face further decreased tool wear. HPC intensity should be chosen based on knowledge of the cutting process. A very intense HPC above 140 bars can lead to mechanical damage to the cutting edge or unmachined surface by chip blasting but using a 60-bar HPC can reduce tool wear similarly, without causing further damage to the cutting edge.

Green Metalworking Fluids for Sustainable Machining Operations and Other Sustainable Systems: A Review

Many efforts have been made over the years to minimize the usage of mineral oil-based MWFs. This includes the trail of its alternatives, such as vegetable oil-based MWFs, nanofluids, etc. These alternatives have shown comparable results to mineral oil-based MWFs in producing a better surface finish and machining efficiency. Apart from the conventional flooding of MWFs, several alternative techniques have been developed by researchers to minimize or eliminate the usage of MWFs, including dry machining, high pressure coolant technique, minimum quantity lubrication, etc. which have also demonstrated promising results. This review attempts to highlight the drawbacks of mineral oil-based MWFs and to assess the applicability of vegetable oil-based MWFs in machining applications. Furthermore, other sustainable machining techniques are discussed in the literature review section, which highlight the main issues associated with the mentioned machining operations and their shortcomings based on the most recent literature. From the comprehensive and critical review that was performed, we inferred that the alternative methods are not mature enough at this stage and that they fall behind in some associated outcomes, some of which may be the tribological properties, surface finish or surface roughness, the cutting forces, the amount of working fluid consumed, etc. More efforts are still needed to fully eliminate the use of MWFs. Moreover, the applications of nanofluids in machining operations have been reviewed in this paper. We concluded from the critical review that nanofluids are an emerging technology which have found their place in machining applications due to their excellent thermophysical properties, but are still in their developmental stage, and more detailed studies are needed to make these a cost-effective solution.

A Qualitative Strategy for Fusion of Physics into Empirical Models for Process Anomaly Detection

To facilitate the automated online monitoring of power plants, a systematic and qualitative strategy for anomaly detection is presented. This strategy is essential to provide credible reasoning on why and when an empirical versus hybrid (i.e., physics-supported) approach should be used and to determine the ideal mix of these two approaches for a defined anomaly detection scope. Empirical methods are usually based on pattern, statistical, and causal inference. Hybrid methods include the use of physics models to train and test data methods, reduce data dimensionality, reduce data-model complexity, augment data, and reduce empirical uncertainty; hybrid methods also include the use of data to tune physics models. The presented strategy is driven by key decision points related to data relevance, simple modeling feasibility, data inference, physics-modeling value, data dimensionality, physics knowledge, method of validation, performance, data availability, and suitability for training and testing, cause-effect, entropy inference, and model fitting. The strategy is demonstrated through a pilot use case for the application of anomaly detection to capture a valve packing leak at the high-pressure coolant injection system of a nuclear power plant.