Journal of Thermophysics and Heat Transfer最新文献

{"title":"Shock-Tube Measurements of Radiation for Titan Atmospheric Entry","authors":"Matthew McGilvray, Timothy J. McIntyre, Alex Glenn, Richard G. Morgan","doi":"10.2514/1.t6892","DOIUrl":"https://doi.org/10.2514/1.t6892","url":null,"abstract":"Journal of Thermophysics and Heat Transfer, Ahead of Print. <br/>","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140936772","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}

{"title":"Method for Simulating Heat Conduction Inside Multilayer Thin Wall","authors":"Ningli Chen, Xian Yi, Qiang Wang, Ruidi Liu","doi":"10.2514/1.t6907","DOIUrl":"https://doi.org/10.2514/1.t6907","url":null,"abstract":"Journal of Thermophysics and Heat Transfer, Ahead of Print. <br/>","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140829265","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}

{"title":"Thermal Behavior of Solid Heated by Gaussian Moving Heat Source","authors":"M. Nguyen, N. Laraqi, J. Bauzin, Mehdi-Belkacem Cherikh, Ali Hocine, Zsolt Péter","doi":"10.2514/1.t6953","DOIUrl":"https://doi.org/10.2514/1.t6953","url":null,"abstract":"In this paper, an analytical development is proposed to explicitly calculate the three-dimensional and transient temperature of a solid heated by a Gaussian moving heat source. The moving source dissipates heat in a thin layer near the irradiated surface of the solid and can be constant or pulsed or have any time evolution, depending on the application. The resulting solution requires only one convergent integral over time, which can be quickly computed numerically using, for example, a commercial formal calculation software. On the other hand, the derivative of the temperature with respect to time is fully explicit. We show that the results of the developed analytical solution are in excellent agreement with those of a numerical modeling that we performed under the same conditions. The temperature evolutions and the thermal maps are presented and commented.","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140675414","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}

{"title":"Investigation of Thermal Performance of Heat Exchangers of Inclined-Elliptic-Tube Bundle","authors":"Lahcene Bellahcene, A. Yousfi, Djamel Sahel, Abdelghani Laouer, Souici Mohammed, Müslüm Arıcı, Mohamed Teggar","doi":"10.2514/1.t6941","DOIUrl":"https://doi.org/10.2514/1.t6941","url":null,"abstract":"Passive performance improvement of heat exchangers is cost-effective and crucial for energy efficiency as well as sustainability of thermal systems. In this paper, an investigation is presented on a compact configuration of heat exchanger composed of a bundle of inclined elliptical tubes. The effect of geometrical parameters on the thermal performance of the heat exchanger is investigated for two tube arrangements i.e. inline and staggered configurations. These parameters include longitudinal (SL/a = 3 to 6) and transversal (ST/a = 2.5 to 5.5) pitch ratios. A CFD commercial code is used for simulation of heat transfer and fluid flow. Computations are performed for the Reynolds number range Re = 300-1500. The outcomes indicate higher performance of the staggered arrangement when compared with the inline inclined tubes. The best thermal performance is observed for a staggered configuration with SL/a = 6, ST/a = 5.5 at Re = 1500. Furthermore, correlations are provided for Nusselt number for heat exchangers of inclined elliptic tubes.","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140676138","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}

{"title":"Heat Transfer Enhancement of Microchannel Heat Sink Using Sine Curve Fins","authors":"Ping Liu, Ruiqi Sun, Lianghong Hu, Weihua Wang, Jiadong Ji","doi":"10.2514/1.t6967","DOIUrl":"https://doi.org/10.2514/1.t6967","url":null,"abstract":"In this study, numerical simulations are conducted to investigate the effects of initial models (parallel and symmetrical arrangement) using interruption fins on the flow and heat transfer characteristics of microchannel heat sink (MHS). The results indicate that MHS with symmetrical fin arrangement has a higher Nusselt number and lower thermal resistance. The vortices perpendicular to the flowpath is the main factor of affecting the heat transfer characteristics. Because of the higher vorticity, the channel with symmetrical fins achieves higher heat transfer performance. To further improve the heat transfer performance, three modified models (models III–V) are obtained by adopting the methods of staggered, reducing fin quantity, and adding pin fins, respectively. The staggered arrangement of fins can deepen the secondary flow in the channel, and the additional vortices are formed with adding pin fins, which can enhance heat transfer capacity in models III and V. On the other hand, reducing the number of fins can damage some vortices, which can actually reduce heat transfer performance. It is worth noting that both the staggered fins and the pin fins significantly increase the pressure drops of the channel, while reducing the fins number leads to an obvious decrease in the pressure drop.","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140677091","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}

{"title":"Transient Thermal Spreading Resistance from Isothermal Source in a Circular Flux Tube","authors":"Lisa Steigerwalt Lam, Sahar Goudarzi, Yuri Muzychka","doi":"10.2514/1.t6805","DOIUrl":"https://doi.org/10.2514/1.t6805","url":null,"abstract":"<p>An analytical expression is developed for transient thermal spreading resistance from an isothermal circular source in a cylindrical flux tube as a function of constriction ratio and time. The flux tube is semi-infinite. The spreading resistance expression is obtained from the temperature expression by solving the heat equation. For short times, the dimensionless transient spreading resistance is proportional to dimensionless time based on the square root of the source area. For long times, the dimensionless spreading resistance approaches the values of the corresponding steady-state expression in the literature. For small constriction ratios, dimensionless spreading resistance approaches the classic isothermal half-space limit. A numerical analysis is presented which shows excellent agreement with the analytical solution. Approximate correlations for dimensionless resistance are also presented for both the isothermal and the isoflux cases.</p>","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140570347","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}

{"title":"Sensitivity Analysis of Ionization in Two-Temperature Models of Hypersonic Airflows","authors":"Timothy T. Aiken, Iain. D. Boyd","doi":"10.2514/1.t6909","DOIUrl":"https://doi.org/10.2514/1.t6909","url":null,"abstract":"<p>Plasma generation in hypersonic flows is analyzed using a two-temperature model of nonequilibrium air. The uncertainties in electron number density predictions are assessed for flow scenarios that correspond to both strongly shocked and strongly expanded flows, and the dependencies of the calculated uncertainties on individual input parameters are quantified. Ionization levels behind 5 and 7 km/s normal shocks are found to be most sensitive to the associative ionization reactions producing <span><math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"><mrow><msubsup><mi mathvariant=\"normal\">O</mi><mn>2</mn><mo>+</mo></msubsup></mrow></math></span><span></span> and <span><math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"><mrow><msup><mi>NO</mi><mo>+</mo></msup></mrow></math></span><span></span> in the region of peak electron number density, with nitric oxide kinetics dominating the uncertainty downstream. The higher levels of ionization behind a 9 km/s shock are found to strongly depend on the electron impact ionization of atomic nitrogen as well as the charge exchange between <span><math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"><mrow><msubsup><mi mathvariant=\"normal\">N</mi><mn>2</mn><mo>+</mo></msubsup></mrow></math></span><span></span> and N. Recombining flow scenarios depend on many of the same processes that influence the shocked flows, with the notable addition of the reassociation reaction <span><math altimg=\"eq-00004.gif\" display=\"inline\" overflow=\"scroll\"><mrow><msup><mrow><mi mathvariant=\"normal\">O</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo><msub><mrow><mi mathvariant=\"normal\">N</mi></mrow><mrow><mn>2</mn></mrow></msub><mo stretchy=\"false\">↔</mo><msup><mrow><mi>NO</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo><mi mathvariant=\"normal\">N</mi></mrow></math></span><span></span>, which is responsible for large uncertainties in electron number density in net recombining flows. The results provide valuable insight into the typical magnitude of uncertainty associated with plasma formation predictions in hypersonic flows and identify the parameters that should be targeted in efforts to reduce those uncertainties.</p>","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140570517","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}

{"title":"Natural Convection Around Three Horizontal Cylinders in Vertical Array: A Numerical Approach","authors":"Manoj Kumar Dash, Santosh Kumar Senapati, Aurovinda Mohanty","doi":"10.2514/1.t6925","DOIUrl":"https://doi.org/10.2514/1.t6925","url":null,"abstract":"<p>The present numerical study explores the flow physics and heat transfer characteristics around three unconfined inline horizontally placed cylinders arranged in a vertical array subjected to ambient air. It investigates the effect of Rayleigh number (i.e., 10² ≤ <i>Ra</i> ≤ 10⁶) and the center-to-center spacing (1≤ <i>S/D</i> ≤ 9). The study shows that the augmentation or reduction of heat transfer rate from an individual cylinder in the array to that of a single unconfined cylinder under identical conditions strongly depends on the separation distance and Rayleigh number. Moreover, the average <i>Nu</i> from the bottom cylinder deteriorates only at very close spacing, whereas after <i>S/D</i> ≥ 3, it attains an asymptotic value to that of a single cylinder. The heat transfer rates from the middle and top cylinders relative to a single cylinder also deteriorate drastically at close spacing. In contrast, a slight enhancement is observed at relatively large spacing and higher <i>Ra</i>.</p>","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140570434","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}

{"title":"Inverse Estimation of Thermal Contact Resistance Between Two Layers of Cylindrical Wall","authors":"Bin Li, Qiang Liu, Keli He","doi":"10.2514/1.t6952","DOIUrl":"https://doi.org/10.2514/1.t6952","url":null,"abstract":"<p>This study presents a method for estimating the space-dependent thermal contact resistance between the two-layer walls of a furnace using the boundary element method (BEM) and conjugate gradient method (CGM) for the heat conduction problem. The global solution equation in matrix form is derived using the interface conditions, and the BEM is used to solve the direct problem. The CGM minimizes the objective function and calculates the sensitivity coefficients with the complex variable derivation method (CVDM). Comparative results show that the present approach is more accurate, stable, and efficient than the conventional CGM, which is attributed to the calculation of the sensitivity coefficients by CVDM. The effects of the value of thermal contact resistance, thermal conductivity ratio, Biot number, initial guess, measurement error, and the number and position of measurement points on the inversion results are also analyzed. Finally, the effectiveness of this approach is demonstrated through numerical examples, and the inversion results show its stability, efficiency, and accuracy in identifying different and complex distributions of thermal contact resistance. Furthermore, this approach is feasible for nonintrusive measurement, which is very meaningful in practical applications.</p>","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140570359","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}

{"title":"Effects of Thermal and Chemical Nonequilibrium on Response of Charring Ablative Materials","authors":"Volkan Coskun, Cuneyt Sert","doi":"10.2514/1.t6786","DOIUrl":"https://doi.org/10.2514/1.t6786","url":null,"abstract":"<p>A material response solver that predicts the response of charring ablative materials under different degrees of physical modeling complexity is developed. The solver provides a versatile environment for engineering analyses and incorporates a third-party library for the evaluation of thermodynamic/transport properties of pyrolysis gas mixture and chemical kinetics, if necessary. Thermal nonequilibrium between the solid and the gas phases is considered using the two-equation model. A novel reactor network approach is used for modeling pyrolysis gas flow inside the porous ablative material, allowing simulations with various gas compositions and reaction mechanisms. Effects of chemical and thermal nonequilibrium and influences of the porosity and permeability of the porous structure on the response of charring ablative materials are explored. It is observed that higher porosity and smaller permeability values induce local thermal equilibrium, and chemical reactions increase the temperature differences between the phases.</p>","PeriodicalId":17482,"journal":{"name":"Journal of Thermophysics and Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140570343","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}