International Journal of Heat and Mass Transfer最新文献

{"title":"A novel coupled DPM-LevelSet model to accurately predict the particulate fouling front in a forced circulation crystallizer","authors":"Jamal Darand,&nbsp;Ali Jafarian","doi":"10.1016/j.ijheatmasstransfer.2025.127250","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127250","url":null,"abstract":"<div><div>A major concern with FC crystallizer heat exchanger in ZLD technology is the accumulation of particulate matter, leading to a gradual decline in its performance. The study employed an innovative coupled DPM-LevelSet model in the OpenFOAM software to simulate the calcium carbonate particulate fouling in FC heat exchanger. The k-ω SST model was used to account for turbulence, while the LevelSet model was employed to accurately capture the fouling front and conjugate heat transfer. Upon results validation, the investigation focused on examining the progressive evolution of the fouling front on the inner side of heat exchanger tube and its complex interplay with hydrodynamics. The research findings indicated that the proposed model is a promising tool for accurately estimating the local heat transfer rate of the evolving fouling front during the particulate deposition process. Results revealed that the fluctuation in fouling front and heat transfer rate are significant attributes of this mechanism. Furthermore, fouling rate was more pronounced at the tube entrance compared to the downstream region, causing an abrupt drop in fouling front temperature and heat transfer. Moreover, the heat transfer ratio, <span><math><mrow><msub><mover><mrow><mover><mi>q</mi><mo>¨</mo></mover></mrow><mo>‾</mo></mover><mrow><mi>f</mi><mi>o</mi><mi>u</mi><mi>l</mi><mi>e</mi><mi>d</mi></mrow></msub><mo>/</mo><msub><mover><mrow><mover><mi>q</mi><mo>¨</mo></mover></mrow><mo>‾</mo></mover><mrow><mi>c</mi><mi>l</mi><mi>e</mi><mi>a</mi><mi>n</mi></mrow></msub></mrow></math></span>, exhibits a substantial decrease, especially in the tube entrance vicinity, suggesting the presence of a thick fouling layer in that region.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127250"},"PeriodicalIF":5.0,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An efficient thermal buffer utilizing pressure-driven close-contact melting","authors":"Yongping Huang ,&nbsp;Hao Zhai ,&nbsp;Chengbin Zhang","doi":"10.1016/j.ijheatmasstransfer.2025.127225","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127225","url":null,"abstract":"<div><div>The thermal management of high-heat-flux electronics requires both efficient and uniform cooling solutions. This study presents an innovative thermal buffer design concept employing pressure-driven close-contact melting (CCM) to address this challenge. A quasi-steady numerical model coupling flow, thermal, and force fields is developed to investigate the pressure-driven CCM mechanism. Moreover, the influences of pressure and chip layout on pressure-driven CCM performance are investigated. Comparative studies with constrained melting and gravity self-driven CCM reveal that pressure-driven CCM delivers superior performance, achieving an 85.8 % reduction in total melting time, 23.2 % lower equivalent thermal resistance, and a 52.6 % improvement in temperature uniformity under identical conditions specific to this work. Furthermore, multi-chip configurations demonstrate significantly lower equivalent thermal resistance compared to single-chip layouts, with uniform arrangements exhibiting optimal thermal performance through minimized chip temperatures and enhanced temperature uniformity. Regarding the total melting time, heat flux wields a more pronounced influence than that of pressure. However, as the values of both heat flux and pressure increase further, their effects follow a non-linear pattern of attenuation. Increased pressure results in a decrease in the chip's steady-state temperature, especially when heat flux levels are high. Moreover, as the critical temperature increases, the disparities in the maximum heat flux under diverse pressure conditions become more conspicuous. These findings demonstrate that external forces critically enhance thermal limits under extreme conditions, establishing pressure-driven CCM as a promising solution for advanced thermal management systems in high-power electronic applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127225"},"PeriodicalIF":5.0,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation on the dynamics of water vapor desorption–migration–adsorption in shale saturated with methane of various pressures","authors":"Tingting Liu,&nbsp;Qingchun Yu","doi":"10.1016/j.ijheatmasstransfer.2025.127270","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127270","url":null,"abstract":"<div><div>Water and methane coexist in shale reservoirs. Water desorption–adsorption dynamics at methane pressure is highly important for energy extraction and environmental protection. Water vapor desorption–adsorption experiments in shales saturated with CH₄ of different pressures were performed. A dynamic adsorption model for describing gas adsorption was developed. A method for calculating the effective water vapor permeability based on desorption–adsorption data was proposed. The experimental and computational results suggest that the water vapor permeability during desorption was greater than that during adsorption, and both decreased over time at different rates. Based on the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, interfacial forces were used to describe the interaction between water vapor and shale. The interfacial force first decreased and then increased with increasing water film thickness, which was great for pores with small sizes. The interfacial force magnitude characterized the adsorption strength and affected the desorption and adsorption rates. The early, middle, and late adsorption stages were controlled by gas flow, gas flow/interfacial force, and interfacial force, respectively. The influence of interfacial forces on the decrease in desorption rate with time was more pronounced than that of adsorption. The interfacial force effect on desorption increased, and that on adsorption decreased with increasing methane pressure. The water vapor permeability at desorption–adsorption equilibrium increased with increasing methane pressure.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127270"},"PeriodicalIF":5.0,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Manipulation of nonreciprocal radiative heat transfer in a two-body system composed of graphene-covered hBN metasurfaces","authors":"Bosen Chen ,&nbsp;Haishan Tian ,&nbsp;Leyong Jiang ,&nbsp;Xiaohu Wu","doi":"10.1016/j.ijheatmasstransfer.2025.127271","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127271","url":null,"abstract":"<div><div>Active manipulation of near-field radiative heat transfer (NFRHT) has important application prospects in thermal management and energy conversion. In this paper, we explore nonreciprocal NFRHT in a two-body system, which consists of graphene-covered hexagonal boron nitride (hBN) metasurfaces. Our results indicate that the strong coupling between nonreciprocal surface plasmon polaritons (NSPPs) in graphene and hyperbolic phonon polaritons (HPPs) in the hBN metasurface confers a unique advantage to the use of a drift bias current for manipulating NFRHT. When the vacuum gap is below a specific threshold, increasing the drift current velocity enhances the heat transfer coefficient (HTC) by several times its initial value. Furthermore, numerical simulations reveal that variations in drift current velocity directly affect both the dispersion relationship and photon transmission coefficient (PTC) distribution of NSPPs, thereby enabling effective manipulation of NFRHT. Additionally, we examined how graphene's chemical potential and the filling fraction of hBN metasurfaces influence radiative heat transfer. Given the critical importance of diverse control strategies for NFRHT in micro‐ and nanoscale thermal radiation devices, we believe that this study serves as a valuable reference for advancing efficient thermal management systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127271"},"PeriodicalIF":5.0,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 coefficient modeling for downward saturated boiling flows in vertical pipes","authors":"Yuki Wada ,&nbsp;Yasuteru Sibamoto ,&nbsp;Takashi Hibiki","doi":"10.1016/j.ijheatmasstransfer.2025.127219","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127219","url":null,"abstract":"<div><div>Two saturated boiling heat transfer correlations for downward flows in vertical circular pipes depending on wall superheat or wall heat flux as input parameters were developed based on a heat transfer experimental database. Owing to the absence of heat transfer correlations specifically developed for downward flows, existing heat transfer correlations for different flow directions were evaluated to determine their applicability to predicting the downward flow heat transfer coefficient. The results revealed that even the most accurate correlation showed a mean absolute percentage error (<em>MAPE</em>) of 66.5 %, highlighting the need for improving predictive performance. In response, the downward flow heat transfer correlation was modeled by integrating a nucleate boiling heat transfer term and a forced convection heat transfer term. The Dong-Hibiki correlation, a two-component, two-phase heat transfer correlation for downward flows, was adopted for the forced convection heat transfer term. The Forster-Zuber correlation, developed as a wall superheat function, and the Cooper correlation, developed as a wall heat flux function, were used for the nucleate boiling term to develop the heat transfer correlations where either wall superheat or wall heat flux is known. Notably, the Dong-Hibiki correlation has been validated over a wide range of experimental conditions. A correction factor was applied to the nucleate boiling term to address errors caused by applying Foster-Zuber and Cooper correlations to downward flows. The two developed correlations achieved an <em>MAPE</em> value of approximately 20 %, representing an improvement of roughly 40 % over existing correlations of heat transfer coefficients.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127219"},"PeriodicalIF":5.0,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on bubble slide characteristics in narrow rectangular blistering channels","authors":"Kexin Liu ,&nbsp;Tianzhou Xie ,&nbsp;Ming Ding ,&nbsp;Xiaxin Cao ,&nbsp;Jianjun Xu","doi":"10.1016/j.ijheatmasstransfer.2025.127268","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127268","url":null,"abstract":"<div><div>Plate-shaped fuel element is a type of nuclear fuel with superior performance and promising development prospects. Blistering of the cladding is a unique failure mode of plate-shaped fuel element, which may occur after the long-term operation of the reactor due to the high local pressure of the fission gas released by the fuel pellets, causing local deformation of the cladding. In flow boiling, sliding bubbles can enhance quenching heat transfer, thereby improving the heat transfer efficiency of the coolant. Therefore, it is necessary to study sliding bubbles. However, the sliding characteristics of bubbles in the blistering channel have not been thoroughly investigated at present. This article is based on the visual experimental study of subcooled boiling in narrow rectangular blistering channels with vertical upward flow. Data on bubble slide velocity and growth diameter were obtained, and the influence of different thermal parameters and geometric structures on bubble slide characteristics was analyzed. The experimental results show that the bubble slide velocity and diameter after bubbles nucleating in the blistering channels rapidly increase in the initial stage and slowly change in the subsequent stage. The geometric structure of blisters has an impact on the bubble slide velocity but has almost no effect on the growth rate of sliding bubbles. The existing empirical correlations cannot accurately predict the velocity and growth diameter of sliding bubbles under blister conditions. The new correlations are proposed to predict bubble slide velocity and growth diameter, and the predicted results are in good agreement with experimental values.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127268"},"PeriodicalIF":5.0,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near-field radiative heat transfer between nanoparticles mediated by acoustic phonon polaritons","authors":"Shuo Chen ,&nbsp;Chengrong Zeng ,&nbsp;Haotuo Liu ,&nbsp;Yang Hu ,&nbsp;Xiaohu Wu ,&nbsp;Ceji Fu","doi":"10.1016/j.ijheatmasstransfer.2025.127263","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127263","url":null,"abstract":"<div><div>Phonon polaritons (PhPs) in natural hyperbolic materials exhibit a high density of electromagnetic states, enabling the efficient enhancement and manipulation of near-field energy transport. In this study, we theoretically investigate the substrate-mediated polaritonic effect on near-field radiative heat transfer between two nanoparticles (NPs) in proximity to a slab of biaxial hyperbolic material <em>α</em>-MoO₃. Compared to conventional PhPs in a freestanding <em>α</em>-MoO₃ slab, acoustic phonon polaritons (APhPs) supported by an <em>α</em>-MoO₃/dielectric spacer/gold heterostructure can either enhance or suppress near-field thermal radiation. This is attributed to the gap-dependent electromagnetic field confinement and propagation length of the APhPs, which jointly influence the radiative energy transfer. Interestingly, even when NPs are located near the <em>α</em>-MoO₃/gold heterostructure, thermal radiation can be suppressed in comparison to the system without a reflective surface. Furthermore, our research demonstrates an improvement in the near-field coupling between propagating APhPs and the localized surface modes of NPs by rotating the <em>α</em>-MoO₃ crystal around the [001] crystalline direction. Notably, we show that an in-plane rotated <em>α</em>-MoO₃ slab offers a modulation contrast ratio in radiative heat transfer exceeding 7000 between “ON” and “OFF” states. Therefore, these findings provide valuable guidance for controlling non-contact energy exchange at the nanoscale.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127263"},"PeriodicalIF":5.0,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical analysis on flow and heat transfer performance of sCO2 in a vertical helically U-tube","authors":"Yunlei Wu ,&nbsp;Tingting Ren ,&nbsp;Lu Huang ,&nbsp;Xiantao Zhang ,&nbsp;Yingni Yu ,&nbsp;Peng Liu","doi":"10.1016/j.ijheatmasstransfer.2025.127265","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127265","url":null,"abstract":"<div><div>Developing compact exchanger is of great significance for the design of efficient supercritical carbon dioxide (sCO₂) cycles. In this study, a vertical helically U-tube (VHUT) is proposed and the numerical model is established to investigate flow and heat transfer performance (FHTP) of sCO₂ in VHUT. Flow pattern and heat transfer mechanism are analyzed in detail though comparing with vertical U-tube (VUT). The results indicate that vortex is generated because of the centrifugal force inducing by helix structure, and the elongate local high temperature areas are appeared on the inside wall of helix structure. In addition, the heat transfer deterioration is almost completely suppressed. Consequently, the average heat transfer coefficient (<em>h_avg</em>) of VHUT is significantly enhanced by 46.49 %-56.97 % when compared to that of VUT, accompanied by 41.65 %-1785.57 % increase in pressure drop per unit length (<em>∆P_u</em>). Moreover, the effect of geometric parameters including coil diameters (<em>D</em>), pitches (<em>p</em>) and bend diameters (<em>d_bend</em>), operational conditions (heat flux <em>q</em>, pressure <em>P</em>, mass flux <em>G</em>) on FHTP are examined. Results demonstrate that <em>h_avg</em> increases as decreasing <em>D, p, d_bend</em> and <em>q</em> and increasing <em>G</em> and <em>P</em>, while <em>∆P_u</em> increases as increasing <em>D, q</em> and <em>G</em> and declining <em>p, d_bend</em> and <em>P</em>.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127265"},"PeriodicalIF":5.0,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Curvature influence on flow and heat transfer in a concentric annulus: Conventional and sensitized Reynolds stress modeling study","authors":"Xiaoyu Wang,&nbsp;Jeanette Hussong,&nbsp;Suad Jakirlić","doi":"10.1016/j.ijheatmasstransfer.2025.127192","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127192","url":null,"abstract":"&lt;div&gt;&lt;div&gt;A computational study was carried out on turbulent flow in a concentric annular pipe with a Reynolds number of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;8900&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, subjected to double-sided uniform wall heating with a heat flux ratio of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;q&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∗&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;q&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;′&lt;/mo&gt;&lt;mo&gt;′&lt;/mo&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;q&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;′&lt;/mo&gt;&lt;mo&gt;′&lt;/mo&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. The computations were performed over a range of curvature parameters, that is radius ratio of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, 0.1, and 0.01, implying an increased difference in transverse curvature between the inner convex and outer concave pipe walls. The turbulence is modeled by a conventional differential near-wall Reynolds stress model (RSM) and its eddy-resolving version. The latter model represents an extension of the conventional formulation that accounts for turbulence fluctuations within the sensitized Reynolds-averaged Navier–Stokes (RANS) computational framework. The RSM’s eddy-resolving capability is achieved by introducing an additional production term in the scale-determining transport equation to selectively enhance turbulence production, in accordance with the Scale-Adaptive Simulation strategy. The thermal field is modeled using the classical gradient diffusion approach to heat flux, considering different formulations of the corresponding diffusion coefficient. The respective results for the mean flow and thermal field properties and the associated second-order statistics are analyzed in detail along with the available reference DNS data for a weaker transverse curvature influence corresponding to &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;mo&gt;≥&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. While this influence is not as strong at the outer concave wall, where the near-wall behavior of all flow variables resembles that of fully-developed flow in a pipe, the mean flow and thermal properties, as well as the associated turbulence correlations, depart noticeably from equilibrium conditions at the inner convex wall. This is particularly dramatic as the radius ratio decreases to &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;01&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, further enhancing the transverse curvature effects in terms of strengthening the asymmetry of all flow quantity profiles toward the inner annulu","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127192"},"PeriodicalIF":5.0,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mathematical analysis of capillary thermal mass flow sensors for gas and liquid flow measurement","authors":"Taig Young Kim","doi":"10.1016/j.ijheatmasstransfer.2025.127216","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127216","url":null,"abstract":"<div><div>An analytical temperature solution for a capillary thermal mass flow sensor (CTMFS) was derived and validated against a detailed thermofluidic numerical model. Approximate formulas for predicting mass flow rates in gases and liquids were developed using a Taylor series expansion of the temperature difference equation between the exit and entrance of the heater zone. Interestingly, while the gas flow rate was linearly proportional to the measured temperature difference, the liquid flow rate was inversely proportional to it. This divergence arises from the differing dominance of heat transfer mechanisms: conduction through the capillary wall in gases and convection within the flow in liquids. In gases, mass flow measurement occurs under conduction-dominant conditions, where convection-induced temperature differences remain within a linear range. In liquids, the high flow heat capacity rate renders wall conduction negligible, resulting in an inverse linear relationship between flow rate and temperature difference. While gas flow measurements exhibit increased nonlinearity at higher flow rates, liquid flow measurements encounter nonlinearity challenges at low flow rates. To quantify these effects, degrees of nonlinearity for gas and liquid flows were defined, providing criteria for establishing upper and lower flow rate limits, respectively. Design parameters for gas flow sensors involve a trade-off between linearity and sensitivity, whereas liquid flow sensitivity is primarily governed by heater power. This study presents novel insights into the measurement principles and design guidelines for CTMFS, contributing to improved accuracy in both gas and liquid flow measurements.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"249 ","pages":"Article 127216"},"PeriodicalIF":5.0,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}