Two Nuclear Safety Advisory Letters (NSALs), advise operators of PWRs that they may assume, in accident analyses, that certain safety and relief valves can open, relieve water, and then reseat properly. The NSALs claim water that exits the reactor coolant system (RCS) can be made up by water that is delivered into the RCS by the emergency core coolant system (ECCS). For example, during an inadvertent operation of the ECCS (IOECCS) event, The NSALs claim, “since the cause of the water relief is the ECCS flow, the magnitude of the leak will be less than or equivalent to that of the ECCS (i.e., operation of the ECCS maintains RCS inventory during the postulated event and establishes the magnitude of the subject leak).” A comparison of ECCS flow to water relief, at relevant RCS pressures, indicates that water relief, during an IOECCS, cannot be dismissed as a leak. Critical flow calculations indicate that ECCS flow cannot replace RCS inventory that is relieved, as water, through the pressurizer relief and safety valves when RCS pressures are near nominal operating levels. At much lower pressures, the ECCS could offset the water relief. However, by then the IOECCS will have been either resolved, or will have developed into a loss of coolant accident (LOCA). The NSALs were published in 1993 and 2007. NRC did not question the NSALs’ advice until 2015, when it was found in a licensee’s application for a power uprating. The licensee might have submitted a false statement, in support of its application.
{"title":"Water Relief Through Safety or Relief Valves is not Just a Leak","authors":"Samuel Miranda","doi":"10.1115/1.4056619","DOIUrl":"https://doi.org/10.1115/1.4056619","url":null,"abstract":"\u0000 Two Nuclear Safety Advisory Letters (NSALs), advise operators of PWRs that they may assume, in accident analyses, that certain safety and relief valves can open, relieve water, and then reseat properly. The NSALs claim water that exits the reactor coolant system (RCS) can be made up by water that is delivered into the RCS by the emergency core coolant system (ECCS). For example, during an inadvertent operation of the ECCS (IOECCS) event, The NSALs claim, “since the cause of the water relief is the ECCS flow, the magnitude of the leak will be less than or equivalent to that of the ECCS (i.e., operation of the ECCS maintains RCS inventory during the postulated event and establishes the magnitude of the subject leak).” A comparison of ECCS flow to water relief, at relevant RCS pressures, indicates that water relief, during an IOECCS, cannot be dismissed as a leak. Critical flow calculations indicate that ECCS flow cannot replace RCS inventory that is relieved, as water, through the pressurizer relief and safety valves when RCS pressures are near nominal operating levels. At much lower pressures, the ECCS could offset the water relief. However, by then the IOECCS will have been either resolved, or will have developed into a loss of coolant accident (LOCA). The NSALs were published in 1993 and 2007. NRC did not question the NSALs’ advice until 2015, when it was found in a licensee’s application for a power uprating. The licensee might have submitted a false statement, in support of its application.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88676135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shehan Jayasekera, Edward C. Hensel, Risa J. Robinson
Abstract Objective: This study characterizes three commercially available wearable respiratory monitors (WRMs): (1) Hexoskin Smart Garment, (2) Smartex WWS, and (3) Equivital EQ02 LifeMonitor, each with a unique chest motion sensor technology: respiratory inductance plethysmography, piezoresistor, and strain gauge, respectively. WRMs comprise of a body garment with embedded sensors that measure ambulatory chest motion in real-time. Once calibrated, chest motion waveforms from WRMs can be converted to lung volume waveform, which is then used to derive respiratory topography. The aim of this study is to assess and compare these WRMs in terms of: (i) their response signal to chest motion linearity, which is necessary for successful calibration, and (ii) their ability to measure breath-hold, which is a parameter of interest for lung deposition modeling. Methods: A benchtop test setup was built to simulate chest motion in a controlled way to facilitate comparison across the three devices. A staircase square-wave chest motion profile was used to simultaneously assess both signal linearity and ability to measure breath-hold. The respiratory response from the sensors was compared to the simulated chest motion. Results: The Hexoskin showed the best performance in both metrics, whereas the Equivital had the worst performance in both. The Smartex showed moderate ability to measure breath-hold but poor signal linearity. Conclusion: Of the three WRMs tested, the Hexoskin appears to be the best choice for ambulatory lung volume measurement. Significance: This study demonstrates the feasibility of adapting current technology to observe respiratory behavior valuable in many research domains, including tobacco research.
{"title":"Benchtop Characterization of Wearable Respiratory Monitors for Assessing Feasibility of Measuring Lung Volume","authors":"Shehan Jayasekera, Edward C. Hensel, Risa J. Robinson","doi":"10.1115/1.4063340","DOIUrl":"https://doi.org/10.1115/1.4063340","url":null,"abstract":"Abstract Objective: This study characterizes three commercially available wearable respiratory monitors (WRMs): (1) Hexoskin Smart Garment, (2) Smartex WWS, and (3) Equivital EQ02 LifeMonitor, each with a unique chest motion sensor technology: respiratory inductance plethysmography, piezoresistor, and strain gauge, respectively. WRMs comprise of a body garment with embedded sensors that measure ambulatory chest motion in real-time. Once calibrated, chest motion waveforms from WRMs can be converted to lung volume waveform, which is then used to derive respiratory topography. The aim of this study is to assess and compare these WRMs in terms of: (i) their response signal to chest motion linearity, which is necessary for successful calibration, and (ii) their ability to measure breath-hold, which is a parameter of interest for lung deposition modeling. Methods: A benchtop test setup was built to simulate chest motion in a controlled way to facilitate comparison across the three devices. A staircase square-wave chest motion profile was used to simultaneously assess both signal linearity and ability to measure breath-hold. The respiratory response from the sensors was compared to the simulated chest motion. Results: The Hexoskin showed the best performance in both metrics, whereas the Equivital had the worst performance in both. The Smartex showed moderate ability to measure breath-hold but poor signal linearity. Conclusion: Of the three WRMs tested, the Hexoskin appears to be the best choice for ambulatory lung volume measurement. Significance: This study demonstrates the feasibility of adapting current technology to observe respiratory behavior valuable in many research domains, including tobacco research.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135794911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Spray investigations are critical for understanding internal combustion engine combustion. Optimised spray atomisation helps improve engine output/performance and reduce tailpipe emissions. The spray from the injector nozzle depends on nozzle hole diameter, fuel injection pressure, ambient density, pressure and temperature in the spray chamber, and test fuel properties. This study evaluated macroscopic and microscopic spray characteristics of dimethyl ether (DME) and baseline diesel under atmospheric conditions (1.013 bar pressure at 298 K temperature). It correlated the spray parameters with distinctive physicochemical properties of diesel and DME using dimensionless numbers, namely Reynolds number, Weber number, and Ohnesorge number. The fuel injection system consisted of a high-pressure mechanical injection pump and mechanical fuel injectors having an original equipment manufacturer fixed nozzle opening pressure in the constant volume spray chamber. The microscopic spray investigations were performed using a phase Doppler interferometer along the spray direction at three axial distances (50, 70, and 90 mm) from the nozzle. The three orthogonal spray droplet velocities of diesel and DME were compared. The droplet number-size distributions for baseline diesel and DME were compared. Macroscopic spray characteristics were evaluated using high-speed imaging. Reynolds number was higher for DME, leading to more turbulence in the spray and accelerating the spray breakup phenomenon. Weber number of DME was also much higher than baseline diesel due to its lower surface tension. The higher Weber and lower Ohnesorge numbers justified the finer droplets of DME sprays. DME showed superior spray atomization characteristics than baseline diesel, leading to superior fuel–air mixing and efficient and sootless combustion.
{"title":"Macroscopic and Microscopic Spray Characteristics of Dimethyl Ether in a Constant Volume Spray Chamber Using a Mechanical Fuel Injection System for Automotive Applications","authors":"Avinash Kumar Agarwal, Vikram Kumar, Shanti Mehra, Nalini Kanta Mukherjee, Hardikk Valera, Devendra Nene","doi":"10.1115/1.4063202","DOIUrl":"https://doi.org/10.1115/1.4063202","url":null,"abstract":"Abstract Spray investigations are critical for understanding internal combustion engine combustion. Optimised spray atomisation helps improve engine output/performance and reduce tailpipe emissions. The spray from the injector nozzle depends on nozzle hole diameter, fuel injection pressure, ambient density, pressure and temperature in the spray chamber, and test fuel properties. This study evaluated macroscopic and microscopic spray characteristics of dimethyl ether (DME) and baseline diesel under atmospheric conditions (1.013 bar pressure at 298 K temperature). It correlated the spray parameters with distinctive physicochemical properties of diesel and DME using dimensionless numbers, namely Reynolds number, Weber number, and Ohnesorge number. The fuel injection system consisted of a high-pressure mechanical injection pump and mechanical fuel injectors having an original equipment manufacturer fixed nozzle opening pressure in the constant volume spray chamber. The microscopic spray investigations were performed using a phase Doppler interferometer along the spray direction at three axial distances (50, 70, and 90 mm) from the nozzle. The three orthogonal spray droplet velocities of diesel and DME were compared. The droplet number-size distributions for baseline diesel and DME were compared. Macroscopic spray characteristics were evaluated using high-speed imaging. Reynolds number was higher for DME, leading to more turbulence in the spray and accelerating the spray breakup phenomenon. Weber number of DME was also much higher than baseline diesel due to its lower surface tension. The higher Weber and lower Ohnesorge numbers justified the finer droplets of DME sprays. DME showed superior spray atomization characteristics than baseline diesel, leading to superior fuel–air mixing and efficient and sootless combustion.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135838417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Javed, Fayyaz, Muhammad Waqas, Agha Muhammad Jazim, Muddassar Sharif, Sikandar Khan
About nine million barrels of gasoline are consumed daily by automobile engines. Out of this, roughly 2.25 million barrels are effectively used by the engine to generate power, whereas the rest is wasted due to engine inefficiencies. There is a dire need to bring up a more efficient engine, since even an effort for a 1% increase in efficiency would result in savings of almost $6 million daily worldwide. In this study, first, a conventional poppet valve engine configuration for a 70cc engine was analyzed. Then, based on the engine efficiency contributing parameters, a novel Independent Rotary Valve (IRV) engine configuration was proposed. The proposed engine configuration was analyzed for the same 70cc engine. The LOTUS Engine software was used for the thermodynamic investigation of intake valve closing angle for getting maximum values of volumetric efficiency, brake power, and brake torque at different speeds and intake valve closing angles. It has been found that the proposed engine configuration resulted in approximately 1.165% increase in thermal efficiency by a decrease in air-fuel mixture pumping work. In addition, a 13% increase in volumetric efficiency, a 13% increase in brake torque, and an 18% increase in brake power were found, through the use of independent valve actuation. Also, an increase in mechanical efficiency is expected, due to the added simplicity of the proposed IRV as compared to the conventional poppet valve system. This increase has been verified analytically and by numerical modeling performed in ANSYS FLUENT. The proposed IRV engine configuration is thus a more efficient, more powerful, less complicated, more stable, and an environmentally safer engine.
{"title":"A Comparative Study of the Conventional Poppet Valve and the Proposed Novel Independent Rotary Valve Configurations for Improving Efficiency of the Internal Combustion Engine","authors":"H. Javed, Fayyaz, Muhammad Waqas, Agha Muhammad Jazim, Muddassar Sharif, Sikandar Khan","doi":"10.1115/1.4062280","DOIUrl":"https://doi.org/10.1115/1.4062280","url":null,"abstract":"\u0000 About nine million barrels of gasoline are consumed daily by automobile engines. Out of this, roughly 2.25 million barrels are effectively used by the engine to generate power, whereas the rest is wasted due to engine inefficiencies. There is a dire need to bring up a more efficient engine, since even an effort for a 1% increase in efficiency would result in savings of almost $6 million daily worldwide. In this study, first, a conventional poppet valve engine configuration for a 70cc engine was analyzed. Then, based on the engine efficiency contributing parameters, a novel Independent Rotary Valve (IRV) engine configuration was proposed. The proposed engine configuration was analyzed for the same 70cc engine. The LOTUS Engine software was used for the thermodynamic investigation of intake valve closing angle for getting maximum values of volumetric efficiency, brake power, and brake torque at different speeds and intake valve closing angles. It has been found that the proposed engine configuration resulted in approximately 1.165% increase in thermal efficiency by a decrease in air-fuel mixture pumping work. In addition, a 13% increase in volumetric efficiency, a 13% increase in brake torque, and an 18% increase in brake power were found, through the use of independent valve actuation. Also, an increase in mechanical efficiency is expected, due to the added simplicity of the proposed IRV as compared to the conventional poppet valve system. This increase has been verified analytically and by numerical modeling performed in ANSYS FLUENT. The proposed IRV engine configuration is thus a more efficient, more powerful, less complicated, more stable, and an environmentally safer engine.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83723853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract To achieve optimal results, femtosecond laser machining requires precise control of system variables such as Regenerative Amplifier Divider, Frequency, and Laser Power. To this end, two regression models, multi-layer perceptron (MLP) regression and Gaussian process regression (GPR) were used to define the complex relationships between these parameters of the laser system and the resulting diameter of a dimple fabricated on a 304 stainless-steel substrate by a 0.2-second laser pulse. In order to quantify dimple diameter accurately and quickly, machine vision was implemented as a processing step while incorporating minimal error. Both regression models were investigated by training with datasets containing 300, 600, 900, and 1210 data points to assess the effect of the dataset size on the training time and accuracy. Results showed that the GPR was approximately six times faster than the MLP model for all of the datasets evaluated. The GPR model accuracy stabilized at approximately 20% error when using more than 300 data points and training times of less than 5 s. In contrast, the MLP model accuracy stabilized at roughly 33% error when using more than 900 data points and training times ranging from 30 to 40 s. It was concluded that GPR performed much faster and more accurately than MLP regression and is more suitable for work with femtosecond laser machining.
{"title":"Exploring Machine Learning and Machine Vision in Femtosecond Laser Machining","authors":"Julia K. Hoskins, Han Hu, Min Zou","doi":"10.1115/1.4063646","DOIUrl":"https://doi.org/10.1115/1.4063646","url":null,"abstract":"Abstract To achieve optimal results, femtosecond laser machining requires precise control of system variables such as Regenerative Amplifier Divider, Frequency, and Laser Power. To this end, two regression models, multi-layer perceptron (MLP) regression and Gaussian process regression (GPR) were used to define the complex relationships between these parameters of the laser system and the resulting diameter of a dimple fabricated on a 304 stainless-steel substrate by a 0.2-second laser pulse. In order to quantify dimple diameter accurately and quickly, machine vision was implemented as a processing step while incorporating minimal error. Both regression models were investigated by training with datasets containing 300, 600, 900, and 1210 data points to assess the effect of the dataset size on the training time and accuracy. Results showed that the GPR was approximately six times faster than the MLP model for all of the datasets evaluated. The GPR model accuracy stabilized at approximately 20% error when using more than 300 data points and training times of less than 5 s. In contrast, the MLP model accuracy stabilized at roughly 33% error when using more than 900 data points and training times ranging from 30 to 40 s. It was concluded that GPR performed much faster and more accurately than MLP regression and is more suitable for work with femtosecond laser machining.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135448463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Wellbore leakage is a concern for abandoned oil and gas wells due to greenhouse gas emissions. The leakage mechanisms and resulting integrity are not well understood. Therefore, researchers have used analytical and numerical models to investigate wellbore integrity. An analytical solution, a finite element model without failure mechanisms, and a finite element model with failure criteria were developed and compared. The benefits and shortcomings of each model were discussed, and the different models were compared with three case study wells. The results of this work show that all three numerical models predict debonding between the cement sheath and the casing. However, including the failure criteria in the models proved to be critical in predicting correct stress distributions.
{"title":"Comparison of Numerical Methods That Predict Wellbore Cement Sheath Integrity","authors":"Jarrett Wise, Runar Nygaard","doi":"10.1115/1.4063342","DOIUrl":"https://doi.org/10.1115/1.4063342","url":null,"abstract":"Abstract Wellbore leakage is a concern for abandoned oil and gas wells due to greenhouse gas emissions. The leakage mechanisms and resulting integrity are not well understood. Therefore, researchers have used analytical and numerical models to investigate wellbore integrity. An analytical solution, a finite element model without failure mechanisms, and a finite element model with failure criteria were developed and compared. The benefits and shortcomings of each model were discussed, and the different models were compared with three case study wells. The results of this work show that all three numerical models predict debonding between the cement sheath and the casing. However, including the failure criteria in the models proved to be critical in predicting correct stress distributions.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135794917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Collin Prebenda, B. Fernandes, Thomas Griffin, Jonathan A. Markowitz, Keagan Carson, Yi Zheng
Harmful algal blooms (HABs), specifically Microcystis aeruginosa (MA), present a serious global problem to bodies of water. HABs are the rapid growth of toxic algae species in a waterway. These algae species are known to cause irritation, nausea, and vomiting in humans, and even more severe side effects in smaller organisms. Climate change and human development have caused these harmful blooms to become more prevalent in recent years. Current commercial and academic algae detection methods were researched and found to be highly restrictive or expensive. This creates the need for a monitoring device that fills this niche, which the team attempted to do. Regarding the detection of MA, the peak spectral absorbances were determined to be at wavelengths of 430 nm and 680 nm. The handheld harmful algae monitoring device directs these specific wavelengths of light matching the peak absorptions of MA through a sample. The relative intensity of light after passing through the sample is measured and used to determine the presence and concentration of MA. This detection method is low cost, is portable, and will provide efficient and precise results with the hope of enabling a variety of users on a large scale. With proper calibration and more research, the handheld harmful algae monitoring device has the potential of being highly accurate and capable of testing nonpure samples.
{"title":"Determination of Microcystis aeruginosa Concentration Using Two Discrete Wavelengths","authors":"Collin Prebenda, B. Fernandes, Thomas Griffin, Jonathan A. Markowitz, Keagan Carson, Yi Zheng","doi":"10.1115/1.4056964","DOIUrl":"https://doi.org/10.1115/1.4056964","url":null,"abstract":"\u0000 Harmful algal blooms (HABs), specifically Microcystis aeruginosa (MA), present a serious global problem to bodies of water. HABs are the rapid growth of toxic algae species in a waterway. These algae species are known to cause irritation, nausea, and vomiting in humans, and even more severe side effects in smaller organisms. Climate change and human development have caused these harmful blooms to become more prevalent in recent years. Current commercial and academic algae detection methods were researched and found to be highly restrictive or expensive. This creates the need for a monitoring device that fills this niche, which the team attempted to do. Regarding the detection of MA, the peak spectral absorbances were determined to be at wavelengths of 430 nm and 680 nm. The handheld harmful algae monitoring device directs these specific wavelengths of light matching the peak absorptions of MA through a sample. The relative intensity of light after passing through the sample is measured and used to determine the presence and concentration of MA. This detection method is low cost, is portable, and will provide efficient and precise results with the hope of enabling a variety of users on a large scale. With proper calibration and more research, the handheld harmful algae monitoring device has the potential of being highly accurate and capable of testing nonpure samples.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75332770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Orkhan Khankishiyev, S. Salehi, C. Vivas, R. Nygaard, Danny Rehg
Models of the enhanced geothermal systems (EGS) in super-hot igneous rocks have demonstrated significantly higher heat transfer rates and power production compared to conventional geothermal systems. On the other hand, along with the high upfront costs, the major geological and technical challenges associated with drilling super-hot EGS wells in igneous rocks constrain the development of geothermal systems and prevent their worldwide application. Meanwhile, geothermal energy development in sedimentary basins could provide clean energy production with relatively lower investment costs compared to super-hot EGS development in igneous rocks. A significant amount of data, knowledge, and expertise has been gathered through decades of drilling and development of oil and gas wells in sedimentary basins. Application of this experience and data for geothermal drilling can eliminate and reduce costs of subsurface data gathering, well drilling, and completion. This paper investigates the economic viability of geothermal energy production systems in sedimentary basins. The study provides initial time-to-hit temperature (THT) and cost-to-hit temperature (CHT) maps across the US based on the well depth, total drilling and completion time, and total well cost data. Combined with sedimentary basin maps and underground temperature maps, THT and CHT maps could be utilized to place EGS wells and other geothermal systems applications at the most favorable locations in the US.
{"title":"Techno-Economic Investigation of Geothermal Development in Sedimentary Basins","authors":"Orkhan Khankishiyev, S. Salehi, C. Vivas, R. Nygaard, Danny Rehg","doi":"10.1115/1.4062412","DOIUrl":"https://doi.org/10.1115/1.4062412","url":null,"abstract":"\u0000 Models of the enhanced geothermal systems (EGS) in super-hot igneous rocks have demonstrated significantly higher heat transfer rates and power production compared to conventional geothermal systems. On the other hand, along with the high upfront costs, the major geological and technical challenges associated with drilling super-hot EGS wells in igneous rocks constrain the development of geothermal systems and prevent their worldwide application. Meanwhile, geothermal energy development in sedimentary basins could provide clean energy production with relatively lower investment costs compared to super-hot EGS development in igneous rocks. A significant amount of data, knowledge, and expertise has been gathered through decades of drilling and development of oil and gas wells in sedimentary basins. Application of this experience and data for geothermal drilling can eliminate and reduce costs of subsurface data gathering, well drilling, and completion. This paper investigates the economic viability of geothermal energy production systems in sedimentary basins. The study provides initial time-to-hit temperature (THT) and cost-to-hit temperature (CHT) maps across the US based on the well depth, total drilling and completion time, and total well cost data. Combined with sedimentary basin maps and underground temperature maps, THT and CHT maps could be utilized to place EGS wells and other geothermal systems applications at the most favorable locations in the US.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83864218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jatin Prakash, Shruti Singh, Ankur Miglani, P. Kankar
Solenoid operated direction control valves, responsible for regulating the flow of fluid in hydraulic circuit highly relies on the control current for their actuation. The control currents supplied to the solenoid generate the electromagnetic force required for switching of valves by mechanical movement of spools inside. The deterioration in control current leads to the degradation in electromagnetic force and thus the spool takes longer to initiate as well as terminate the switching phenomenon. This delay or lag potentially causes the pressure, flow and power fluctuation, and unintended impacts on the system. This article presents a comparative analysis of detecting these anomalies by acquiring pressure signals across the valve using extreme gradient boosting (XGBoost) and one-dimensional convolution neural network (CNN). Four handcrafted statistical features and four fractal dimensions train XGBoost whereas 1D CNN with six hidden layers utilizes the raw signal of net pressure change across the valve. XGBoost predicts the switching behavior at an accuracy of 99.68%, and 1D CNN performs at its maximum possible accuracy (100%). The very narrow gap signifies the nearly equal significance of both of these different category classifiers. As XGBoost cannot handle the raw signals, the pre-processing increases the time consumption while 1D CNN does not require deep architecture and efficiently maps the complexity of the hydraulic system using pressure signals.
{"title":"Pressure Signal-Based Analysis of Anomalies in Switching Behavior of a Two-Way Directional Control Valve","authors":"Jatin Prakash, Shruti Singh, Ankur Miglani, P. Kankar","doi":"10.1115/1.4056474","DOIUrl":"https://doi.org/10.1115/1.4056474","url":null,"abstract":"\u0000 Solenoid operated direction control valves, responsible for regulating the flow of fluid in hydraulic circuit highly relies on the control current for their actuation. The control currents supplied to the solenoid generate the electromagnetic force required for switching of valves by mechanical movement of spools inside. The deterioration in control current leads to the degradation in electromagnetic force and thus the spool takes longer to initiate as well as terminate the switching phenomenon. This delay or lag potentially causes the pressure, flow and power fluctuation, and unintended impacts on the system. This article presents a comparative analysis of detecting these anomalies by acquiring pressure signals across the valve using extreme gradient boosting (XGBoost) and one-dimensional convolution neural network (CNN). Four handcrafted statistical features and four fractal dimensions train XGBoost whereas 1D CNN with six hidden layers utilizes the raw signal of net pressure change across the valve. XGBoost predicts the switching behavior at an accuracy of 99.68%, and 1D CNN performs at its maximum possible accuracy (100%). The very narrow gap signifies the nearly equal significance of both of these different category classifiers. As XGBoost cannot handle the raw signals, the pre-processing increases the time consumption while 1D CNN does not require deep architecture and efficiently maps the complexity of the hydraulic system using pressure signals.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89468724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Rifat Hasan Rubel, M. Ferdows, Tahia Tazin, T. A. Bég, O. Anwar Bég, Ali Kadir
Abstract A theoretical study in stagnation point flow is presented where melting heat transfer effects of carbon nanotube (CNT) from a stretching surface is appeared. Both carbon nanotubes like single-wall CNT (SWCNT) and multiwall CNT (MWCNT) are homogeneously dispersed in the base fluid. As the ordinary (or base) fluids, water and kerosene oil are employed. A set of nonlinear ordinary differential equations with appropriate boundary conditions is formed by transforming the governing equations via similarity transformations. The transformed nonlinear ordinary differential equations are then solved numerically using the bvp4c solver in matlab, an efficient numerical finite difference method. The impact of nanoparticle volume fraction, velocity, melting, stretching parameter, and CNT type on transport characteristics are explored and visualized graphically and in tabular forms. Verification of the matlab computations with available data in certain limiting cases is included showing excellent agreement. Existence of dual (upper and lower branch) solution is shown for a certain range of stretching sheet parameter. The obtained dual solutions are examined for velocity and temperature in detail. A stability analysis demonstrates that the first solution is a stable solution, and the second solution is an unstable solution. Local skin friction and local Nusselt number are also computed in order to determine critical values that can permit dual solutions. It is observed that when a dimensionless melting parameter is greater than 1, SWCNT nanofluids attain greater velocities than MWCNT nanofluids for water as well as kerosene oil base fluids. Moreover, the flow is accelerated for SWCNT compared with MWCNT for both water and kerosene oil. With increasing stretching parameter, the heat transfer rate (Nusselt number) increases, whereas skin friction coefficients decrease. Higher skin friction and Nusselt number are obtained for SWCNTs compared to MWCNTs due to their greater density and thermal conductivity. The study is relevant to phase change manufacturing fluid dynamics of nanomaterials.
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