This study delves into the realm of numerical investigation of the heat transfer performance of nanofluids as coolants for prismatic batteries. Nanofluids are being employed in battery cooling systems to enhance overall thermal management and ensure the safe operation of batteries, particularly in situations involving high heat generation. In this study, different types of nanofluids were used along with a base fluid of ethylene glycol-water (EG-water 50%). The energy equations consider the effects of viscous dissipation and heat generation. The model generates a set of nonlinear partial differential equations (PDEs), which can be transformed into ordinary differential equations (ODEs) using appropriate similarity variables. These ODEs are then solved numerically by employing the Range-Kutta-Fehlberg method along with the shooting method to obtain solutions. The simulations in both 2D and 3D showcase the results for various parameters pertaining to thermal and velocity fields, heat transfer rate, and drag force. The findings reveal that heat generation leads to a staggering increase in temperature of 78.22%. However, using aluminum nanoparticles as opposed to copper nanoparticles quickly reduced the battery's maximum temperature by 9.31%. The exceptional heat generation strengths of CuO-EG and Al2O3-EG nanofluids also resulted in a significant increase in their heat transfer rates of around 40.42% and 42.13%, respectively. Additionally, the aluminum NPs exhibited a more rapid heat transfer rate of 4.06% when compared to the copper nanoparticles.
{"title":"Numerical Investigation of Nanofluid as a Coolant in a Prismatic Battery for Thermal Management Systems","authors":"V. B, Sung Chul Kim, Sang Woo Joo, Santosh Chavan","doi":"10.1115/1.4064232","DOIUrl":"https://doi.org/10.1115/1.4064232","url":null,"abstract":"\u0000 This study delves into the realm of numerical investigation of the heat transfer performance of nanofluids as coolants for prismatic batteries. Nanofluids are being employed in battery cooling systems to enhance overall thermal management and ensure the safe operation of batteries, particularly in situations involving high heat generation. In this study, different types of nanofluids were used along with a base fluid of ethylene glycol-water (EG-water 50%). The energy equations consider the effects of viscous dissipation and heat generation. The model generates a set of nonlinear partial differential equations (PDEs), which can be transformed into ordinary differential equations (ODEs) using appropriate similarity variables. These ODEs are then solved numerically by employing the Range-Kutta-Fehlberg method along with the shooting method to obtain solutions. The simulations in both 2D and 3D showcase the results for various parameters pertaining to thermal and velocity fields, heat transfer rate, and drag force. The findings reveal that heat generation leads to a staggering increase in temperature of 78.22%. However, using aluminum nanoparticles as opposed to copper nanoparticles quickly reduced the battery's maximum temperature by 9.31%. The exceptional heat generation strengths of CuO-EG and Al2O3-EG nanofluids also resulted in a significant increase in their heat transfer rates of around 40.42% and 42.13%, respectively. Additionally, the aluminum NPs exhibited a more rapid heat transfer rate of 4.06% when compared to the copper nanoparticles.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"30 18","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138591035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, experiments are conducted with conventional rectangular channels of two different aspect ratios (AR=w/d) for the horizontal boiling flow conditions at atmospheric pressure. Distilled water was used as the working substance. The heat transfer coefficients (HTC) were measured for mass fluxes and heat fluxes ranging from 85.94 kg/m2-s to 343.77 kg/m2-s and 10 kW/m2 to 100 kW/m2 respectively and at inlet subcooled temperatures of 303K, 313K and 323K. Visualization of the boiling phenomenon was done using a high-speed camera for the two channels under similar conditions. The results show that the AR has a dominant effect on the HTC. At low heat flux values, higher HTC was noticed for the channel of higher AR (AR= 1.25) whereas, at high heat flux conditions, the HTC is higher for the channel of lower AR (AR= 0.2). With an increase in inlet subcooled temperature, the HTC decreased for both channels due to increased thermal boundary layer thickness and reduced bubble formation. Further, the channel of AR=1.25 with ribs/fins performed better than the smooth channel due to the high bubble nucleation rate.
{"title":"EFFECT OF RIBS/FINS AND ASPECT RATIO ON FLOW BOILING CHARACTERISTICS IN CONVENTIONAL CHANNELS","authors":"Madan K, Sathyabhama A","doi":"10.1115/1.4064168","DOIUrl":"https://doi.org/10.1115/1.4064168","url":null,"abstract":"\u0000 In this work, experiments are conducted with conventional rectangular channels of two different aspect ratios (AR=w/d) for the horizontal boiling flow conditions at atmospheric pressure. Distilled water was used as the working substance. The heat transfer coefficients (HTC) were measured for mass fluxes and heat fluxes ranging from 85.94 kg/m2-s to 343.77 kg/m2-s and 10 kW/m2 to 100 kW/m2 respectively and at inlet subcooled temperatures of 303K, 313K and 323K. Visualization of the boiling phenomenon was done using a high-speed camera for the two channels under similar conditions. The results show that the AR has a dominant effect on the HTC. At low heat flux values, higher HTC was noticed for the channel of higher AR (AR= 1.25) whereas, at high heat flux conditions, the HTC is higher for the channel of lower AR (AR= 0.2). With an increase in inlet subcooled temperature, the HTC decreased for both channels due to increased thermal boundary layer thickness and reduced bubble formation. Further, the channel of AR=1.25 with ribs/fins performed better than the smooth channel due to the high bubble nucleation rate.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"49 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138622810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A prediction method for temperature distributions in compact heat exchanger was developed by modeling the microchannel as a fluid-saturated porous medium. The study focused on the mathematical formulas and solution methods for convective heat transfer of heat core. Firstly, the correlation mechanisms and laws between the key parameters' effects and heat transfer were revealed and explained. The results show that the temperature/pressure/velocity contours obtained from the porous-media model are consistent with those of the tube-matrix. The longitudinal pitch has little effect on the flow characteristics and the Reynolds number. Transverse pitch has significant effects on the flow characteristics and the Reynolds number. Under different pitch conditions, the Nusselt number obtained by Zukauskas-correlation is larger than that of porous-media model, which is larger than that of tube-matrix. Secondly, the simplified model and fast calculation method were developed. Tube bundles of the heat exchanger core were modelled as micro-channels and theoretically as fluid-saturated porous structures. Results show that the heat transfer performance predicted by the micro-channels, tube-matrix, and porous-media model is consistent under the same boundary conditions. These results are consistent with the experiment. In addition, the computing cost and time required for the porous-media and micro-channels model is relatively reduced. Especially for the micro-channels model, the calculating time is less than one tenth of the original. Compared with the time-consuming numerical method, the new analytical solution has the advantages of cost and speed.
{"title":"Prediction of heat transfer for compact tube heat exchanger based on porous models","authors":"Xuheng Chen, Na Li, Xin Zhou, Zhenyu Duan","doi":"10.1115/1.4064169","DOIUrl":"https://doi.org/10.1115/1.4064169","url":null,"abstract":"A prediction method for temperature distributions in compact heat exchanger was developed by modeling the microchannel as a fluid-saturated porous medium. The study focused on the mathematical formulas and solution methods for convective heat transfer of heat core. Firstly, the correlation mechanisms and laws between the key parameters' effects and heat transfer were revealed and explained. The results show that the temperature/pressure/velocity contours obtained from the porous-media model are consistent with those of the tube-matrix. The longitudinal pitch has little effect on the flow characteristics and the Reynolds number. Transverse pitch has significant effects on the flow characteristics and the Reynolds number. Under different pitch conditions, the Nusselt number obtained by Zukauskas-correlation is larger than that of porous-media model, which is larger than that of tube-matrix. Secondly, the simplified model and fast calculation method were developed. Tube bundles of the heat exchanger core were modelled as micro-channels and theoretically as fluid-saturated porous structures. Results show that the heat transfer performance predicted by the micro-channels, tube-matrix, and porous-media model is consistent under the same boundary conditions. These results are consistent with the experiment. In addition, the computing cost and time required for the porous-media and micro-channels model is relatively reduced. Especially for the micro-channels model, the calculating time is less than one tenth of the original. Compared with the time-consuming numerical method, the new analytical solution has the advantages of cost and speed.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"6 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139205734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to estimate the average and stagnation Nusselt numbers for turbulent flow for impingement cooling of a flat plate with a helically coiled air jet, a new artificial neural network (ANN) model is presented in the present study. A new dataset of stagnation and average Nusselt numbers as a function of Reynolds number (Re) varied from 5000 to 30000, nozzle plate spacing ratio changed from 2 to 8, and jet helical angle varied from 0 to 60 degrees was created based on an experimental investigation. The ANN structure composed of three layers with hidden neurons of 14-10-8. The training process comprises feed-forward propagation of the selected input parameters, back-propagation with biases and weight adjustments, and loss function evaluation for the training and validation datasets. The activation function of the output layer is a linear function, and the rectified linear unit activation function is utilized in the hidden layers. The adaptive moment estimation algorithm(ADAM) is employed to minimize the loss function to accelerate the ANN training. For the ANN model, the mean absolute percent error values were 2.35% for the average Nusselt number and 2.52% for the stagnation Nusselt number. As a result, greater accuracy was obtained as compared to generalized correlations. According to the comparison of projected data with the outcomes of earlier experiments, the derived model's performance was validated and the findings showed outstanding accuracy.
为了估算螺旋卷绕气流冲击冷却平板时湍流的平均和停滞努塞尔特数，本研究提出了一种新的人工神经网络（ANN）模型。在实验研究的基础上，创建了一个新的数据集，其中包括停滞和平均努塞尔特数与雷诺数（Re）从 5000 到 30000、喷嘴板间距比从 2 到 8 以及喷射螺旋角从 0 到 60 度之间的函数关系。ANN 结构由三层组成，隐神经元数为 14-10-8。训练过程包括选定输入参数的前馈传播、带偏置和权重调整的反向传播，以及训练和验证数据集的损失函数评估。输出层的激活函数为线性函数，隐层采用整流线性单元激活函数。采用自适应矩估计算法（ADAM）来最小化损失函数，以加速 ANN 的训练。对于 ANN 模型，平均努塞尔特数的平均绝对误差值为 2.35%，停滞努塞尔特数的平均绝对误差值为 2.52%。因此，与广义相关性相比，该模型获得了更高的精度。根据预测数据与早期实验结果的比较，得出的模型性能得到了验证，结果显示了出色的准确性。
{"title":"Artificial neural networks application on average and stagnation Nusselt number prediction for impingement cooling of flat plate with helically coiled air jet","authors":"Hany Fawaz, Mostafa Osama, Hussein Maghrabie","doi":"10.1115/1.4064139","DOIUrl":"https://doi.org/10.1115/1.4064139","url":null,"abstract":"In order to estimate the average and stagnation Nusselt numbers for turbulent flow for impingement cooling of a flat plate with a helically coiled air jet, a new artificial neural network (ANN) model is presented in the present study. A new dataset of stagnation and average Nusselt numbers as a function of Reynolds number (Re) varied from 5000 to 30000, nozzle plate spacing ratio changed from 2 to 8, and jet helical angle varied from 0 to 60 degrees was created based on an experimental investigation. The ANN structure composed of three layers with hidden neurons of 14-10-8. The training process comprises feed-forward propagation of the selected input parameters, back-propagation with biases and weight adjustments, and loss function evaluation for the training and validation datasets. The activation function of the output layer is a linear function, and the rectified linear unit activation function is utilized in the hidden layers. The adaptive moment estimation algorithm(ADAM) is employed to minimize the loss function to accelerate the ANN training. For the ANN model, the mean absolute percent error values were 2.35% for the average Nusselt number and 2.52% for the stagnation Nusselt number. As a result, greater accuracy was obtained as compared to generalized correlations. According to the comparison of projected data with the outcomes of earlier experiments, the derived model's performance was validated and the findings showed outstanding accuracy.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"27 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139245332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nanoparticle coating on copper substrates like carbon nanotubes (CNT) and graphene oxide (GO) is a promising method to enhance the surface properties as well as improve the boiling heat transfer characteristics. Main objective of the present investigation is to study the influence of the nanocomposite coating on the performance of pool boiling heat transfer. CNT+GO nanomaterials are coated on copper substrates via the dip coating method by varying the concentration of the nanomaterial. Morphological analysis, surface roughness, and wettability behaviour of the coating are also observed. The result shows that CNT+GO increases the surface roughness of the samples and the coated samples are in super hydrophilic in nature. Comparing with the uncoated sample, the coated sample shows the maximum increase in critical heat flux and heat transfer co-efficient is 145.76% and 259.08%, respectively. A high-speed camera is used to study the bubble dynamics. Bubble diameter, departure frequency, and site density are also calculated and presented.
{"title":"Pool boiling of CNT+GO nano materials coated copper substrate: An Experimental study","authors":"Ranjan Kumar, Dipak Sen, Sandip Kumar Mandal","doi":"10.1115/1.4064134","DOIUrl":"https://doi.org/10.1115/1.4064134","url":null,"abstract":"Nanoparticle coating on copper substrates like carbon nanotubes (CNT) and graphene oxide (GO) is a promising method to enhance the surface properties as well as improve the boiling heat transfer characteristics. Main objective of the present investigation is to study the influence of the nanocomposite coating on the performance of pool boiling heat transfer. CNT+GO nanomaterials are coated on copper substrates via the dip coating method by varying the concentration of the nanomaterial. Morphological analysis, surface roughness, and wettability behaviour of the coating are also observed. The result shows that CNT+GO increases the surface roughness of the samples and the coated samples are in super hydrophilic in nature. Comparing with the uncoated sample, the coated sample shows the maximum increase in critical heat flux and heat transfer co-efficient is 145.76% and 259.08%, respectively. A high-speed camera is used to study the bubble dynamics. Bubble diameter, departure frequency, and site density are also calculated and presented.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"131 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139246226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ground source heat pump (GSHP) systems have emerged as energy-efficient alternate systems for conventional the Air-Source Air-Conditioning (ASAC) systems for space heating and cooling applications. GSHPs have gained widespread popularity globally and are extensively utilized in residential and commercial buildings. However, in countries like India where both space cooling and heating are required, it becomes essential to evaluate the performance of GSHP system, especially during peak hour operation to estimate peak load energy demand. This research paper tries to identify the energy efficiency of GSHP system during peak-hour operations in comparison to ASAC system using experimental techniques. Experimental trials were conducted in a laboratory equipped with a single unit of 17.58 kW cooling/heating capacity GSHP system and a 17.57 kW cooling/heating ASAC system (two units of 7.023 kW and 10.548 kW). Experimental trials were conducted in peak summer in the month of June for cooling mode operation and January for heating mode operation for Roorkee weather conditions in northern part of India. The performance of both the systems was compared by defining instantaneous COP and cyclic COP. The instantaneous COP was found to be higher for both the systems during peak hour cooling and heating mode operations. Energy-saving analysis indicates that the ground source heat pump system saves 36.85% and 38.65% of electrical energy in cooling and heating modes, respectively, compared to the ASAC system.
{"title":"Experimental Investigation of Energy-Saving Potential of Ground Source Heat Pump during Peak Hour Operations","authors":"Shammy Kumar, Krishnan Murugesan, Elangovan Rajasekar","doi":"10.1115/1.4064138","DOIUrl":"https://doi.org/10.1115/1.4064138","url":null,"abstract":"Ground source heat pump (GSHP) systems have emerged as energy-efficient alternate systems for conventional the Air-Source Air-Conditioning (ASAC) systems for space heating and cooling applications. GSHPs have gained widespread popularity globally and are extensively utilized in residential and commercial buildings. However, in countries like India where both space cooling and heating are required, it becomes essential to evaluate the performance of GSHP system, especially during peak hour operation to estimate peak load energy demand. This research paper tries to identify the energy efficiency of GSHP system during peak-hour operations in comparison to ASAC system using experimental techniques. Experimental trials were conducted in a laboratory equipped with a single unit of 17.58 kW cooling/heating capacity GSHP system and a 17.57 kW cooling/heating ASAC system (two units of 7.023 kW and 10.548 kW). Experimental trials were conducted in peak summer in the month of June for cooling mode operation and January for heating mode operation for Roorkee weather conditions in northern part of India. The performance of both the systems was compared by defining instantaneous COP and cyclic COP. The instantaneous COP was found to be higher for both the systems during peak hour cooling and heating mode operations. Energy-saving analysis indicates that the ground source heat pump system saves 36.85% and 38.65% of electrical energy in cooling and heating modes, respectively, compared to the ASAC system.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"33 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139242569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mercy Vasan A, Sridharan M, Gopalakrishnan V, Shiva Ranjani R S
This research aims to demonstrate the advantages of combining machine learning algorithms with the realm of thermo-fluidic applications. The primary objective of this investigation is to pinpoint the essential hydrodynamic input parameters that can maximize the advantages of fluidization and lead to an improved design for a CFB furnace, utilizing the Apriori algorithm. Also, this algorithm is capable of identifying the right combinations of parameters that can produce maximum fluidization performance. The end results suggested by this AA are validated using computational fluid dynamics package. For this, the transient behavior of a scaled down (1:20) reactor model of a real time industrial CFB boiler is simulated using ANSYS FLUENT 18.0. In specific, the effects of fluidizing velocities, inventory heights of the bed, and particle sizes recommended by the AA are investigated. Here, the effects are assessed in terms of volume fraction distribution and axial velocity profile distribution profiles. From the results of simulations, it was clearly found that 2 m/s inlet velocity produced good circulating fluidized bed patterns on a bed inventory height of 0.5 m for a mean particle size of 200 microns. The results obtained from the simulations are once again validated visually against snapshots obtained during real-time laboratory fluidization experimental runs. Also, it is found that the manual time taken to identify the right combinations of parameters is drastically reduced by this method as against conventional optimization algorithm and trial -error methods.
本研究旨在展示将机器学习算法与热流体应用领域相结合的优势。这项研究的主要目的是利用 Apriori 算法，找出能够最大限度发挥流化优势的基本流体动力输入参数，从而改进 CFB 炉的设计。此外，该算法还能确定能产生最大流化性能的正确参数组合。通过使用计算流体动力学软件包，验证了 AA 所建议的最终结果。为此，使用 ANSYS FLUENT 18.0 模拟了实时工业 CFB 锅炉按比例缩小（1:20）的反应器模型的瞬态行为。具体而言，研究了流化速度、床层高度和 AA 推荐的颗粒尺寸的影响。在此，从体积分数分布和轴向速度分布曲线的角度对这些影响进行了评估。模拟结果清楚地表明，在平均粒径为 200 微米的情况下，2 米/秒的入口速度可在 0.5 米的床层库存高度上产生良好的循环流化床模式。模拟结果与实验室实时流化实验运行时获得的快照再次进行了直观验证。此外，与传统的优化算法和试错法相比，该方法大大减少了人工确定正确参数组合所需的时间。
{"title":"MACHINE LEARNING AIDED NUMERICAL AND EXPERIMENTAL INVESTIGATION OF HYDRODYNAMIC PERFORMANCE IN THE CIRCULATING FLUIDIZED BED BOILER","authors":"Mercy Vasan A, Sridharan M, Gopalakrishnan V, Shiva Ranjani R S","doi":"10.1115/1.4064077","DOIUrl":"https://doi.org/10.1115/1.4064077","url":null,"abstract":"This research aims to demonstrate the advantages of combining machine learning algorithms with the realm of thermo-fluidic applications. The primary objective of this investigation is to pinpoint the essential hydrodynamic input parameters that can maximize the advantages of fluidization and lead to an improved design for a CFB furnace, utilizing the Apriori algorithm. Also, this algorithm is capable of identifying the right combinations of parameters that can produce maximum fluidization performance. The end results suggested by this AA are validated using computational fluid dynamics package. For this, the transient behavior of a scaled down (1:20) reactor model of a real time industrial CFB boiler is simulated using ANSYS FLUENT 18.0. In specific, the effects of fluidizing velocities, inventory heights of the bed, and particle sizes recommended by the AA are investigated. Here, the effects are assessed in terms of volume fraction distribution and axial velocity profile distribution profiles. From the results of simulations, it was clearly found that 2 m/s inlet velocity produced good circulating fluidized bed patterns on a bed inventory height of 0.5 m for a mean particle size of 200 microns. The results obtained from the simulations are once again validated visually against snapshots obtained during real-time laboratory fluidization experimental runs. Also, it is found that the manual time taken to identify the right combinations of parameters is drastically reduced by this method as against conventional optimization algorithm and trial -error methods.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"19 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139266532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Predicting heat transfer mechanisms through solids and fluids is a continuously demanding research topic since accurate and fast temperature calculation is crucial in many engineering and industrial applications. The paper presents a new model to calculate the temperature variation of solids and fluids instantly, in less than 0.04 s, for the whole simulation period based on a novel computational framework of deep learning. The partial differential equation, such as the heat transfer equation, can be solved directly at any point according to a well-known boundary condition point without the need for domain discretization. Therefore, instant and accurate temperature calculation is achieved with the minimum computational resources. The proposed deep learning model can be applied in many engineering applications and products by using it in online thermal monitoring or digital twin technology. The new model is well validated by comparing the temperature values obtained from the deep learning model with the experimental temperature measurements. Moreover, a computational cost comparison with other numerical models is conducted to prove the high efficiency of the proposed deep learning model, where MATLAB is utilized to develop the required codes.
{"title":"Using neural networks for thermal analysis of heat conduction","authors":"Daud Abdoh","doi":"10.1115/1.4064076","DOIUrl":"https://doi.org/10.1115/1.4064076","url":null,"abstract":"Predicting heat transfer mechanisms through solids and fluids is a continuously demanding research topic since accurate and fast temperature calculation is crucial in many engineering and industrial applications. The paper presents a new model to calculate the temperature variation of solids and fluids instantly, in less than 0.04 s, for the whole simulation period based on a novel computational framework of deep learning. The partial differential equation, such as the heat transfer equation, can be solved directly at any point according to a well-known boundary condition point without the need for domain discretization. Therefore, instant and accurate temperature calculation is achieved with the minimum computational resources. The proposed deep learning model can be applied in many engineering applications and products by using it in online thermal monitoring or digital twin technology. The new model is well validated by comparing the temperature values obtained from the deep learning model with the experimental temperature measurements. Moreover, a computational cost comparison with other numerical models is conducted to prove the high efficiency of the proposed deep learning model, where MATLAB is utilized to develop the required codes.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"38 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139265262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper presents an experimental investigation on local heat transfer characteristics of single-phase flow in a plate heat exchanger (PHE). The local heat transfer coefficient is evaluated using a test section with PHE geometry for measuring wall temperature distribution. The test section of 1.5 mm thickness is employed to consider the heat conduction effect of the heat transfer plate. The results indicated that the local heat transfer coefficient is influenced by the development of the thermal boundary layer along the flow direction and the maldistribution of water flows along both the direction perpendicular to the flow and the stacking direction. The harmonic mean heat transfer coefficient calculated by the measured local heat transfer coefficient agrees with the average heat transfer coefficient evaluated by the modified Wilson plot method within ±25 % and within ±16 % for the hot side and the cold side, respectively.
{"title":"Experimental Investigation of Local Heat Transfer Coefficient in a Plate Heat Exchanger Using a Thin Heat Transfer Surface","authors":"Tomoki Hirokawa, Ayarou Yamasaki, Osamu Kawanami","doi":"10.1115/1.4063916","DOIUrl":"https://doi.org/10.1115/1.4063916","url":null,"abstract":"Abstract This paper presents an experimental investigation on local heat transfer characteristics of single-phase flow in a plate heat exchanger (PHE). The local heat transfer coefficient is evaluated using a test section with PHE geometry for measuring wall temperature distribution. The test section of 1.5 mm thickness is employed to consider the heat conduction effect of the heat transfer plate. The results indicated that the local heat transfer coefficient is influenced by the development of the thermal boundary layer along the flow direction and the maldistribution of water flows along both the direction perpendicular to the flow and the stacking direction. The harmonic mean heat transfer coefficient calculated by the measured local heat transfer coefficient agrees with the average heat transfer coefficient evaluated by the modified Wilson plot method within ±25 % and within ±16 % for the hot side and the cold side, respectively.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136262008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dheeraj Kumar, Apurba Layek, Amit Kumar, Rakesh Kumar
Abstract The solar air heater's thermal efficiency is relatively poor owing to the flat collector surface. This article's primary objective is to increase the collectors' thermal efficiency of rectangular ducts of solar air heater by adopting a novel V-shaped twisted rib element with staggering orientation. Experimentations are performed for various flow Reynolds numbers ranging from 3k-21k, roughness pitch-to-rib height ratio ranging from 7-11, and staggering distance to rib height ratio between 2-6. Dispersion of Nusselt number over the collector surface is achieved through liquid crystal thermography technique. Among the varied rib and flow constraints, it is observed that a maximum thermal performance enhancement index of 2.69 is observed, with the optimum value of the roughness parameter at a rib pitch-to-height ratio of 9 and a staggering distance-to-height ratio of 4. Mathematical correlation has also been developed using a regression model to estimate the Nusselt number in terms of non-dimensional roughness parameters. The percentage deviation between the Nusselt number attained from established relationships and the investigational results are found to be giving very satisfactory outcomes. The thermal efficiency of the smooth surface is recognized at 42.64% which increases for the roughened surface of twisted V-ribs to 73.63%. Hence employing twisted V-ribs as an artificial roughness element no doubt increases the Nusselt number, thermohydraulic performance enhancement index, and thermal efficiency, but it also exerts less frictional power of solar air heater.
{"title":"Experimental study for the enhancement of thermal efficiency and development of Nusselt number correlation for the roughened collector of solar air heater","authors":"Dheeraj Kumar, Apurba Layek, Amit Kumar, Rakesh Kumar","doi":"10.1115/1.4063915","DOIUrl":"https://doi.org/10.1115/1.4063915","url":null,"abstract":"Abstract The solar air heater's thermal efficiency is relatively poor owing to the flat collector surface. This article's primary objective is to increase the collectors' thermal efficiency of rectangular ducts of solar air heater by adopting a novel V-shaped twisted rib element with staggering orientation. Experimentations are performed for various flow Reynolds numbers ranging from 3k-21k, roughness pitch-to-rib height ratio ranging from 7-11, and staggering distance to rib height ratio between 2-6. Dispersion of Nusselt number over the collector surface is achieved through liquid crystal thermography technique. Among the varied rib and flow constraints, it is observed that a maximum thermal performance enhancement index of 2.69 is observed, with the optimum value of the roughness parameter at a rib pitch-to-height ratio of 9 and a staggering distance-to-height ratio of 4. Mathematical correlation has also been developed using a regression model to estimate the Nusselt number in terms of non-dimensional roughness parameters. The percentage deviation between the Nusselt number attained from established relationships and the investigational results are found to be giving very satisfactory outcomes. The thermal efficiency of the smooth surface is recognized at 42.64% which increases for the roughened surface of twisted V-ribs to 73.63%. Hence employing twisted V-ribs as an artificial roughness element no doubt increases the Nusselt number, thermohydraulic performance enhancement index, and thermal efficiency, but it also exerts less frictional power of solar air heater.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136262159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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