International Journal of Thermodynamics最新文献

{"title":"The Effect of the Conversion Coefficients of Platinum-Based Resistance Thermometers on the Uncertainty Estimation","authors":"F.M. Patan Alper","doi":"10.5541/ijot.1220322","DOIUrl":"https://doi.org/10.5541/ijot.1220322","url":null,"abstract":"Different types of thermometers (resistance thermometers, thermocouples, liquid in glass thermometers, radiation thermometers, etc.) are used in temperature measurements. Resistance thermometers are among the most reliable types of sensors used for sensitive temperature measurements. The traceability, accuracy and precision of the measurement results are important for the reliability of the measurements. There are many parameters that affect the uncertainty estimation in measurements made with resistance thermometers. One of the parameters to be considered in the uncertainty estimation is the interpolation error in converting the resistance value to temperature. Different methods (ITS-90, Calendar Van Dusen CVD, Polynomial equation) can be used to convert the resistance value to temperature. The problem is that there are differences in the temperature values read using the coefficients obtained by different methods. In this study, the effect of errors from CVD and polynomial equation methods on measurement uncertainty was investigated.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42144735","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}

{"title":"Modeling of the Vapor-Liquid Equilibria Properties of Binary Mixtures for Refrigeration Machinery","authors":"Youcef Maalem, Youcef Tamene, H. Madani","doi":"10.5541/ijot.1140088","DOIUrl":"https://doi.org/10.5541/ijot.1140088","url":null,"abstract":"The presence of both critical and azeotropic states in the vapor-liquid equilibria (VLE) is a very important issue in the chemical and refrigeration engineering. The knowledge of the phase behavior (subcritical phase/supercritical phase) of refrigerant allows designing and optimizing the refrigeration industrials processes. However, it is rare to find data for this information, which poses a great challenge for researchers to develop predictive and correlative thermodynamic models. The present study proposes the computation of the compositions and pressures of critical and azeotropic points of the isothermal VLE as well as the correlation of experimental VLE data. Firstly, experimental data (PTxy) was used to predict the vapor-liquid phase of both critical and azeotropic behaviors and to determine their properties using the relative volatility model. Secondly, the thermodynamic model (PR-MC-WS-NRTL) was applied to correlate the data of the binary refrigerant systems and describe their isothermal (VLE) behavior. The results proved that there is good agreement between predicted values obtained by the developed model and the experimental reference data. The relative error of both critical and azeotropic properties does not exceed 4.3 % for the molar fraction and 7.5 % for the pressure using relative volatility model. On other hand the relative deviation is respectively less than 2.60 % and 2.58 % for the liquid and vapor mole fractions using (PR-MC-WS-NRTL) model. This shows the ability of these models to give a reliable solution to predict and modulate the phase behavior of the binary refrigerant systems.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45608215","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}

{"title":"Thermoelastic Analysis For A Thick Plate Under The Radiation Boundary Conditions","authors":"G. Dhameja, L. Khalsa, V Varghese","doi":"10.5541/ijot.1170342","DOIUrl":"https://doi.org/10.5541/ijot.1170342","url":null,"abstract":"A fractional Cattaneo model for studying the thermoelastic response for a finite thick circular plate with source function is considered. The thick plate is subjected to radiation-type boundary conditions on the upper and lower surfaces, and its curved surface is kept at zero temperature. The theory of integral transformations is used to solve the generalized fractional Cattaneo-type, classical Cattaneo-Vernotte and Fourier heat conduction model. The analytical expressions of displacement components using thermoelastic displacement potentials; and thermal-stress distribution are computed and depicted graphically. The effects of the fractional-order parameter and the relaxation time on the temperature fields and their thermal stresses are investigated. The findings show that the higher the fractional-order parameter, the higher the thermal response. The greater the relaxation period, the longer the heat flux propagates on thick structures.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47142281","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}

{"title":"Investigation of Kalina Cycle for Power Generation from Heat Dissipation of Tarasht Power Plant","authors":"S. Sadri, Seyed Yousef SEYED MOHSENİ","doi":"10.5541/ijot.1214617","DOIUrl":"https://doi.org/10.5541/ijot.1214617","url":null,"abstract":"Fuel consumption optimization in thermal power plants is one of the essential topics in the saving energy field in the world. Then; it is necessary to review and provide solutions to increase efficiency. The present manuscript has recovered the heat dissipation from power plant stacks. The Kalina cycle was studied to use exhaust gases to generate power in the Tarasht power plant. Net power output is calculated at about 2080 kW, which increases the total power production of the plant by about 5%. According to environmental analysis, this cycle will cause less damage to the environment due to lowering the temperature of the exhaust gases in the atmosphere and not using additional fossil fuels. Therefore; it is a good solution for using heat dissipation from power plants. The only thing to consider in this solution (based on economic analysis) is the high construction cost compared to other power plant units.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46571942","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}

{"title":"Design of a Coal Drying System with Solar-Assisted Heat Pump and Waste Heat Utilisation","authors":"M. Ökten","doi":"10.5541/ijot.1219737","DOIUrl":"https://doi.org/10.5541/ijot.1219737","url":null,"abstract":"The increase in global energy demand has directed researchers towards making low-quality coals into an environmentally friendly energy source by reducing their high moisture content. Drying coal is a high-energy and time-consuming process, so reducing the required energy and drying time is crucial for drying technology. Coal drying increases the thermal value of coal and makes it easier to transport. In this study, a coal drying system was designed using waste heat recovery systems, R-134a refrigerant as working fluid, air source heat pumps, and vacuum tube solar collectors to provide hot air. Firstly, the moisture content of the coal and the desired moisture content after drying were determined, and then the heat required to dry the coal was calculated. Next, the capacity of the solar collector required to provide the necessary heat to the heat pump was determined, and the type and capacity of the heat pump that could produce the required heat were selected. Finally, the coal dryer was designed based on the specific requirements of the power plant and the type of coal used. As a result, the coal drying system designed with solar-assisted heat pumps and waste heat utilization can increase the efficiency of coal-fired power plants by reducing the moisture content of coal before combustion.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45328830","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}

{"title":"Thermally-Induced Stresses in a Pre-Buckling State of a Circular Plate within the Fractional-Order Framework","authors":"G. Dhameja, L. Khalsa, V Varghese","doi":"10.5541/ijot.1170364","DOIUrl":"https://doi.org/10.5541/ijot.1170364","url":null,"abstract":"This paper considers a transient thermoelastic problem in an isotropic homogeneous elastic thin circular plate with clamped edges subjected to thermal load within the fractional-order theory framework. The prescribed ramp-type surface temperature is on the plate's top face, while the bottom face is kept at zero. The three-dimensional heat conduction equation is solved using a Laplace transformation and the classical solution method. The Gaver–Stehfest approach was used to invert Laplace domain outcomes. The thermal moment is derived based on temperature change, and its bending stresses are obtained using the resultant moment and resultant forces per unit length. The results are illustrated by numerical calculations considering the material to be an Aluminum-like medium, and corresponding graphs are plotted.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48850508","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}

{"title":"Modelling and Simulation of Existing Geothermal Power Plant: A Case Study of Darajat Geothermal Power Plant","authors":"K. F. A. Sukra, D. Permana, W. Adriansyah","doi":"10.5541/ijot.1118778","DOIUrl":"https://doi.org/10.5541/ijot.1118778","url":null,"abstract":"The electrical energy needs grow every year, increasing awareness and use of renewable energy even higher. Geothermal power plants (GPP) are even ogled as a renewable energy source that has a lot of potential worldwide. Technology for GPP continues to evolve. However, tools for analyzing a system of GPP are still inadequate. In this study, a simple analysis tool was designed. The usefulness of this analysis tool is to be able to know the state of the GPP works. This tool will help simulate the conditions that may occur in the plant system. The simulation results will also be known operating conditions that may occur, so the operator can determine what should be done if things happen. Modeling started using Microsoft Excel, which has been equipped with thermodynamic properties. Modeling includes turbine, condenser, cooling tower, and extraction systems non-condensable gas. After validated, the model run simulation in variations that may occur such as decline in the condition of the condenser and cooling tower and environmental conditions, represented by relative humidity. The simulation with variation of condition will decrease the power generated from turbine 3 – 5%.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48873377","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}

{"title":"Semi-Analytical Solution for Modelling Moving Heat Sources in a Semi-Infinite Medium with Radiative and Convective Boundary Conditions","authors":"A. Metallo","doi":"10.5541/ijot.1097756","DOIUrl":"https://doi.org/10.5541/ijot.1097756","url":null,"abstract":"The weld quality is highly related to the thermal history of the weld and there have been many trials to monitor the quality using an infrared (IR) sensor. To obtain the real temperature of a surface based on the brightness temperature values measured by an IR camera, the emissivity value must be derived. For an accurate assessment of the emissivity, one must be aware of the melting point isotherm. The temperature profiles only depend on three factors during laser processing, specified as constants the characteristics of the material: laser beam speed (v), laser beam diameter (d), and power (P). Predicting the width of the melted zone reached during the welding process as the parameters vary is a tool for helping a quality laser processing and for determination of true temperature in laser welding using IR camera. This study describes the semi-analytical (SA) solution of the heat conduction equation for a localized moving Gaussian heat source with constant parameters on a semi-infinite medium. The solution, simple and quick to obtain, provides information on the width of the melted zone with an average error < 5 %. The outcome is assessed numerically and contrasted with FEM solutions for a Gaussian source, the latter having undergone experimental validation. With two distinct defocus values, def0 and def-6, and by varying the speed and power settings, two separate types of experiments were run. Thus, the SA solution was obtained and compared after the FEM solution had been obtained with a good approximation (max err 4.3 %, average err 2.7 %). Only in regard to the 1AL test is an error more than 5 % detected; in the other case, the average error is 3.75 %. Two more tests at the defocus values of def-4 and def-8 were conducted to confirm the model's validity as the parameters varied. Overall, the average error between the semi-analytical and the FEM solution is 4.1%. The SA solution may be used to effectively estimate the isotherms related to the melting point of aluminum (770 K). This allows to obtain a tool which helps restoring the real temperature based on the brightness values measured by the IR camera during laser welding. At the same time, this effective tool allows to investigate the importance of different processing parameters in laser manufacturing.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47767852","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}

{"title":"Dissociation Constant Studies of 2-Substituted 4-Formylbenzoic Acid based on Conductometric Parameters using Fuoss-Hsia Theories","authors":"Kosrat N. Kaka, R. Omer, Salam G. Taher, W. M. H. Hamad","doi":"10.5541/ijot.1136209","DOIUrl":"https://doi.org/10.5541/ijot.1136209","url":null,"abstract":"The dissociation constant is a quantitative measure of the strength of an acid in solution. This study examines dissociation constant for the series substituted acids like Ortho-alkoxy-4-formylbenzoic acid. The use of (2-methoxy ethanol) as a solvent contributed to the study expected to form free ions or solvent separated ion pair which has been studied with the use conductometric method at different temperatures ranged from 293.15 to 318.15K. The study aims at figuring out dissociation constant, equivalent conductance at infinity dilution, and Walden product by minimization technique using Fuoss-Hsia for both (Modified and Complete) equations. It has been found in the results that the calculated values based on statistical sum square (different between practical and theoretical values) is equivalent conductance at infinity dilution and dissociation constant. It has also been observed that increase the temperature leads to the increase of the molar conductance at infinity dilution, and the increase in association. Moreover, the substituted alkoxy group also affected dissociation of compounds. In this study, the thermodynamic parameters (Ho, Go and So) have also been evaluated and discussed. Finally, the effect of substituent groups on rate of dissociation was studied and explained with agreement to the principles of mesomeric(M) and Inductive effect(I) of substituent groups on dissociation constant.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":"4 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41289451","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}

{"title":"Time-Fractional Cattaneo-Type Thermoelastic Interior-Boundary Value Problem Within A Rigid Ball","authors":"G. Dhameja, L. Khalsa, V Varghese","doi":"10.5541/ijot.1170335","DOIUrl":"https://doi.org/10.5541/ijot.1170335","url":null,"abstract":"The paper discusses the solution of an interior-boundary value problem of one-dimensional time-fractional Cattaneo-type heat conduction and its stress fields for a rigid ball. The interior value problem describes the dependence of the boundary conditions within the ball's inner plane at any instant with a prescribed temperature state, in contrast to the exterior value problem, which relates the known surface temperature to boundary conditions. A single-phase-lag equation with Caputo fractional derivatives is proposed to model the heat equation in a medium subjected to time-dependent physical boundary conditions. The application of the finite spherical Hankel and Laplace transform technique to heat conduction is discussed. The influence of the fractional-order parameter and the relaxation time is examined on the temperature fields and their related stresses. The findings show that the slower the thermal wave, the bigger the fractional-order setting, and the higher the period of relaxation, the slower the heat flux propagates.","PeriodicalId":14438,"journal":{"name":"International Journal of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45217825","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}