Inside Tubes Research Articles

Parallel multiple-chain DRAM probabilistic model for ultrasonic pulse velocity of concrete performance in the pipe of arch bridge

The existing models for predicting the compaction state of concrete inside steel tubes based on ultrasonic wave velocity have a major limitation in that they cannot comprehensively consider concrete compressive strength, instar, and various sources of uncertainties, both subjective and objective. To overcome this limitation, the study introduced a probability model for ultrasonic wave velocity in the concrete performance inside arch bridge steel tubes, based on the parallel multiple-chain Delayed Rejection Adaptive Metropolis (DRAM) algorithm. Initially, the study considers the influence of concrete compressive strength and instar, establishing a simplified deterministic model for predicting concrete compactness inside the tubes. Building on this, the study incorporates material stochastic uncertainty and cognitive uncertainty, deriving analytical expressions for a probabilistic prediction model of concrete compactness. Furthermore, using parallel processing alongside the DRAM algorithm, the study explores how the number of parallel chains and the order of acceptance probabilities influence the probabilistic model parameters. The study selected and updated the posterior distribution information of the probabilistic model parameters. Finally, the effectiveness of the model was validated using experimental data. As shown in the analysis, with better prediction accuracy and lower dispersion, the model not only selects the optimal Markov chain iteration path in a short time, but also corrects the parameters affecting the prediction accuracy of the existing model, and also provides a probabilistic method for correcting the confidence intervals of the existing model.

Experimental and numerical investigation of the thermal - hydraulic performance of flow inside helical coil elliptic tubes

Helical coil tubes are essential in a variety of engineering applications due to their improved heat transfer and compact shape. The current study presents an experimental and numerical investigation of geometrical optimization for helical coil elliptic tubes. Four distinct coil pitch values are examined with a constant perimeter for all geometries and three aspect ratio values (1, 0.75, 0.5) utilizing water as the working fluid across varying the volume flow rates. The helical coil has the same surface area as the tube for each coil. The numerical simulation is conducted using the ANSYS FLUENT CFD software (Version 19.2). The experimental and numerical results indicate that the increase in heat transfer due to an increase in mass flow rate is significantly greater than the improvement gained by changing the aspect ratios. Increasing the volume flow rate to 3 L/min significantly improves the average heat transfer coefficient, with a 66.6 % increase found at a maximum coil pitch of 0.08 m and an aspect ratio of 0.5. Furthermore, a helical coil with an aspect ratio of one (circular cross-section) exhibits the best compromise between pressure drop penalty and heat transfer enhancement, resulting in the greatest hydraulic thermal performance parameter.

Prediction of Heat Transfer during Condensation of Ammonia Inside Tubes and Annuli

Ammonia has been used as a refrigerant since the beginning of the refrigeration industry and it continues to be an important industrial refrigerant. However, there is no well-verified method for predicting heat transfer during condensation in tubes and annuli. Available information is often contradictory, especially about the effect of oil. In this paper, available test data and predictive methods are reviewed. Reliable test data are identified and compared to well-known general correlations. The effect of oil on heat transfer is investigated. The results of this research are presented, and recommendations are made for design calculations.

Microscale heat transfer and phase change mechanisms of carbon dioxide at near-critical conditions

Recent studies highlight the potential benefits of two-phase carbon dioxide (CO2) systems operating near their thermodynamic critical point. Significant heat transfer coefficients and resistance to critical heat flux from improved vapor phase properties can enable heat transfer and reliability enhancements. However, the physical mechanisms of phase change that govern heat transfer behavior in the near-critical regime of reduced pressures (0.85<PR<1, where PR=P/Pcrit) are not well understood. In the present study, subcooled microscale (hydraulic diameter, Dh=500μm) flow boiling experiments are conducted to elucidate the heat transfer behavior near the critical point and the underlying mechanisms that influence it. Experimental data reveals a deviation from the trends predicted by the Cheng correlation (Cheng, L et al., 2008, “New prediction methods for CO2 evaporation inside tubes: Part II—An updated general flow boiling heat transfer model based on flow patterns.” Int. J. Heat Mass Transfer), in particular, displaying a decreasing peak heat transfer coefficient as pressure increases. Heat transfer in the near-critical regime can be further partitioned into two regions: near-critical boiling (0.85<PR<0.96) that exhibits heat transfer highly dependent on surface temperature, and supercritical-like behavior (0.96<PR<1) exhibiting a strong heat transfer dependence on mass flux. High-speed side-view flow visualization reveals the dominant nucleation mechanism (heterogeneous or homogeneous) governs the heat transfer behavior and is adequately predicted using flow inlet conditions. The present study provides a method for predicting nucleation behavior, which, in turn, facilitates the prediction of heat transfer near the critical point. The continuous alteration of heat transfer in the near-critical regime as a function of PR is underscored by this mechanistic insight, bridging the gap between typical flow boiling (PR<0.85) and supercritical heat transfer (PR>1).

Molecular Identification of Fungal Species Isolated from the External Surfaces of Ants Caught from Educational Hospitals in Babol City (2021-2022)

Background. Since the ants play a key role in transmitting microorganisms, it is important to identify the fungal species isolated from the external surfaces of ants caught from hospitals. Therefore, the present study aimed to identify the fungal species isolated from the external surfaces of ants caught from Babol hospitals. Methods. Ants were collected by trapping inside sterile tubes and were washed with normal saline for 20 seconds. Then, 100 µL of the resulting solution was cultured in Sabouraud Dextrose Agar (SDA) medium and incubated for one week at 35C°. Macroscopic, microscopic, and RFLP-PCR molecular techniques were employed to confirm the grown isolates. Results. A total of 79 fungal isolates including 47 isolates of hyaline fungi (59.49%) and 32 isolates of black fungi (40.51%) were obtained from 63 captured ants. Out of 47 cultured fungi, 15 fungi (31.91%) were Aspergillus niger and 15 (31.91%) were A. flavus, 12 (25.53%) were A. fumigatus and 5 isolates were Penicillium (10.63%). Conclusion. Taking into account the increasing number of immunocompromised patients, outbreak of COVID-19 in recent years, and numerous reports about the invasive fungal diseases among COVID-19 patients, it was found necessary to control the ants as carriers of these organisms. Practical Implications. It was necessary to control these insects effectively in order to prevent the increasing prevalence of the fungal diseases among the hospitalized people.

Gas leakage physical simulation and its distributed optical fiber sensing experiments in the casing annulus of injection-production pipe column for underground gas storage

Aiming at the problems of high-pressure gas leakage monitoring of injection-production pipe columns in deep underground gas storage under the high-temperature and high-pressure environment, and the problems that distributed optical fiber sensing system is not convenient to carry out detection accuracy and sensitivity testing and verification in actual wellbores, an experimental device for the pipe column gas leakage simulation test of gas storage wellbore is designed and developed to simulate the actual operation conditions of injection-production wellbores. A distributed optical fiber sensing testing environment is built, and the gas leakage signal analysis and location in the casing annulus of injection-production pipe column for the wellbore of underground gas storage are realized by using a distributed temperature sensing (DTS) system and a distributed acoustic sensing (DAS) system. The high-pressure gas leakage signals of the small crack in the damaged area of the wellbore connection can be obtained through the armored optical cable arranged along the casing annulus of pipe columns in the physical device. The optical fiber and its systems can monitor and detect the change of temperature difference and acoustic vibration field in the perimeter caused by high-pressure gas leakage. The spatial-temporal evolution of the casing annulus leakage law and the purpose of pipe column gas leakage can be realized for the wellbore safety monitoring of underground gas storage. The temperature measurement accuracy and positioning sensitivity of the DTS and DAS systems were simulated and verified by designing the pressure difference between inside and outside annular tubes and the leakage source with an interval of 1.0 m. The effectiveness of the pipe column leakage physical simulation experimental device and the reliability of DTS/DAS testing positioning accuracy are verified. This experimental device based on physical model test and its DTS/DAS testing system effectively verify the feasibility and reliability of distributed optical fiber wellbore leakage monitoring for underground gas storage, and its application provides a novel way for the evaluation and analysis of the wellbore tightness and safety of underground energy storage.

Identifying effective parameters on capillary tube performance with HCFCs, HFCs blends, and hydrocarbon refrigerants: Numerical assessment

This work offers a comprehensive numerical evaluation of the performance of capillary tube utilizing different refrigerants, including HCFCs, HFCs blends (Zeotropic, Azeotropic), and hydrocarbon, such as such as R22, R404A, R407C, R410A, R507A, and R290 refrigerants to predict the critical length of the adiabatic capillary tube. Utilizing a comprehensive thermodynamic model is applied to simulate the behavior of different refrigerants. Moreover, the effective design parameters based on the internal diameter for the adiabatic capillary tube (ACT), inside surface tube roughness, degree of subcooled, metastable region, condenser diameter, design of evaporator pressure (at critical length), condenser operating pressure, and refrigeration capacity are considered. The numerical model is developed based on the governing equations for mass, momentum, and energy, while a specified empirical equations are employed to represent each of the friction factor for single-and-two phase flow and metastable region. The results showed that the longest length of the ACT of 10.5 m revealed with R410A at mass flow rate of 8 g/s compared with 0.25 m at mass flow rate of 16 g/s for R290. Also, the results showed that the minimum value of friction factor of 0.0189 for R410A compared with maximum value of 0.0208 for R407C. The developed model is validated with available experimental results and models under different operation conditions and is found expectable with a good agreement. Where the standard error for different refrigerant with range value between (2.774% to 3.677%). However, the model represents accurate prediction the flow behavior and the thermal performance of the ACT.

TiO2 Nanotube Arrays Inside Ultrafine Ti Tubes with an Aspect Ratio of 2500 for Sensing Needles: The Bubble Effect in a Confined Space.

Capillary metal tubes have attracted considerable interest for flexible electronics, portable devices, trace sampling, and detection. Tailoring the microstructure and wettability inside the capillary tubes is of paramount importance, yet it presents great difficulty because of the spatial confinement. Here, the coupling effect is revealed between the fluidic and electric field induced by bubble motion in a confined space during anodic oxidation. By controlling the bubble regeneration and flow rate, uniform and superhydrophilic TiO2 nanotube arrays are developed throughout the inner surface of an ultrafine Ti tube with a diameter of 0.4mm and length of 1000mm, equivalent to an aspect ratio of 2500 that is the largest value being ever reported. The inner surface of a capillary tube is further coated with a polytetrafluoroethylene layer and explored as a sensing needle for liquid detection in terms of concentration and species. This study provides an innovative approach to tailor the microstructure and wettability in a confined space for functional capillary tubes.

Mechanical response of long-span CFST arch bridges based on the hydration heat temperature effect

As the span of concrete-filled steel tube (CFST) arch bridges increases, the hydration heat temperature effect of concrete inside steel tube becomes more severe, which increases the safety risk during the construction process. Therefore, a numerical simulation of the mechanical response of a long-span CFST arch bridge under the influence of hydration heat was carried out. First, based on the hydration heat conduction theory, a finite element model of the transient temperature field of a CFST arch rib was established. The temperature distribution of the CFST arch rib and its variation with time were revealed, and an approximate formula for the distribution of the hydration heat temperature along the radial direction of the CFST was provided. Subsequently, the variation law of the thermal stress of a CFST during hydration heat release was investigated. Finally, based on the principle of temperature equivalence, a finite element model of the overall CFST arch rib was established to examine the effect of hydration heat on the deformation of the arch rib. The results reveal that the hydration heat temperature field of the CFST arch rib exhibits nonlinear and axisymmetric characteristics. The maximum temperature of the section and the maximum temperature difference can reach 73.5 °C and 33.2 °C, respectively. Because of the influence of the hydration heat, there is a significant stress gradient in the cross section of the arch rib. A maximum radial stress of 2.08 MPa is attained, indicating a risk of concrete cracking. Additionally, the displacement along the transverse and vertical directions of the chord tube exhibits an initial increase, followed by a decrease over time. The maximum transverse displacement of the chord tube reaches 70.6 mm, while the vertical displacement reaches 117.8 mm.

The effect of turbulence on the minimum thickness of a liquid film flowing down a vertical tube

When a liquid flows down a vertical tube at a low flowrate, it may not be able to completely cover the surface as a film, and the flow will comprise a number of rivulets separated by unwetted areas. Predictions of the minimum film thickness and corresponding minimum flowrate below which films cannot be sustained are needed in many industrial heat and mass transfer operations. In this paper a model is developed using the minimum energy method to calculate the minimum film thicknesses that can be maintained for flows down a vertical tube. It is concluded that inclusion of the effect of turbulence in the model can significantly increase the values of the calculated minimum film thicknesses. In these calculations (for 100⁰C water flowing down a 6 mm inside diameter tube) the effect of turbulence increased as the tube to liquid contact angle increased. For a flow at the highest contact angle of 90⁰, the minimum film thickness increased by 22% above the laminar value and the corresponding minimum flowrate increased by 75%. The model presented in this paper can be used to calculate the thermal performance of falling film evaporators over the whole range of flowrate.

Numerical simulation-based design of optimized surfaces for condensation heat transfer

Heat transfer enhancement is a well-established research topic due to its industrial relevance. The advent of 3D printing, also known as additive manufacturing, has opened up the pathway for the design of compact heat exchangers with innovative shapes, complex geometries and smaller size. In particular, additive manufacturing technologies speed up the transition from CAD models to physical prototypes and thus numerical simulation tools for two-phase heat transfer are expected in the future to play a key role for the design of heat exchangers. With regard to filmwise condensation, numerical methods capable to account for all the main forces involved (such as gravity, surface tension, vapor shear stress) must be considered for the optimization of the condensing surfaces. The present study is focused on the preliminary design of innovative shapes for enhancing the condensation heat transfer in a grooved wick heat pipe. Most of the condensation heat transfer studies available in the literature deal with vapor condensing inside tubes or over cylindrical/plain surfaces, while the condensation process occurring inside heat pipes has been less investigated. The grooved wick surfaces must be designed with the aim to promote the drainage of the condensate and minimize the thickness of the liquid film forming over the wick structures. In the present work, the behaviour of different surfaces is studied during condensation of refrigerants by performing Volume of Fluid (VOF) 2D numerical simulations with Ansys®Fluent. The numerical results allow to determine the liquid film thickness and the heat flux distribution along the grooves.

Nanofluid natural convection of hot concentric cylinder in oval-shaped porous cavity at different eccentricity

PurposeThis paper aims to study the effect of concentric hot circular cylinder inside egg-cavity porous-copper nanofluid on natural convection phenomena.Design/methodology/approachThe finite element method–based Galerkin approach is applied to solve numerically the set of governing equations with appropriate boundary conditions.FindingsThe effects of different range parameters, such as Darcy number (10–3 = Da = 10–1), Rayleigh number (103 = Ra = 106), nanoparticle volume fraction (0 = ϑ = 0.06) and eccentricity (−0.3 = e = 0.1) on the fluid flow represent by stream function and heat transfer represent by temperature distribution, local and average Nusselt numbers.Research limitations/implicationsA comparison between oval shape and concentric circular concentric cylinder was investigated.Originality/valueIn the current numerical study, heat transfer by natural convection was identified inside the new design of egg-shaped cavity as a result of the presence of a circular inside it supported by a porous medium filled with a nanofluid. After reviewing previous studies and considering the importance of heat transfer by free convection inside tubes for many applications, to the best of the authors’ knowledge, the current work is the first study that deals with a study and comparison between the common shape (concentric circular tubes) and the new shape (egg-shaped cavity).

A comprehensive analysis of heat transfer in a heat exchanger with simple and perforated twisted tapes based on numerical simulations

One of the most important methods to promote heat transfer (HT) in a heat exchanger (HE) is to use a twisted tape (TT) inside tubes. Therefore, in this paper, the result of the effect of TTs on the Nusselt number (Nu), and the performance coefficient of HEs in a laminar flow are investigated. plain tube (PT), simple TTs and perforated twisted tapes (PTTs) at 3 torsion ratio, blade numbers (N) 2, 4, 6 and 8 in the Reynolds numbers (Re) from 200 to 1000 are investigated. Ansys-Fluent computing software is used for this simulation. The findings indicate a positive correlation between the number of blades and both the Nu and the friction factor. It is important to acknowledge that the objective is to enhance the efficiency of the higher HE. Additionally, since there is an undesirable ratio between the rise of the Nu and the boost of the friction factor, so the HE coefficient decreases as the number of blades in TTs increases, from 6 to 8. The PTT with 6 blades provides the best performance coefficient. Compared to the simple TT, in the PTT, the Nu increases to 15.24%, the friction factor decreases to 22.26%, and the coefficient of thermal performance grows to 18.07%.

Piston-like particle jamming for enhanced stiffness adjustment of soft robotic arm

PurposeStiffness adjusting ability is essential for soft robotic arms to perform complex tasks. A soft state enables dexterous operation and safe interaction, while a rigid state enables large force output or heavy weight carrying. However, making a compact integration of soft actuators with powerful stiffness adjusting mechanisms is challenging. This study aims to develop a piston-like particle jamming mechanism for enhanced stiffness adjustment of a soft robotic arm.Design/methodology/approachThe arm has two pairs of differential tendons for spatial bending, and a jamming core consists of four jamming units with particles sealed inside braided tubes for stiffness adjustment. The jamming core is pushed and pulled smoothly along the tendons by a piston, which is then driven by a motor and a ball screw mechanism.FindingsThe tip displacement of the arm under 150 N jamming force and no more than 0.3 kg load is minimal. The maximum stiffening ratio measured in the experiment under 150 N jamming force is up to 6–25 depends on the bending direction and added load of the arm, which is superior to most of the vacuum powered jamming method.Originality/valueThe proposed robotic arm makes an innovative compact integration of tendon-driven robotic arm and motor-driven piston-like particle jamming mechanism. The jamming force is much larger compared to conventional vacuum-powered systems and results in a superior stiffening ability.

Reflections on use of Monte Carlo methods

Monte Carlo methods have become ubiquitous in our society. Although statistical estimation methods date to earlier times, Monte Carlo (MC) methods were born in 1949 with publication of the paper by Metropolis and Ulam (1949). We address some of the many ways that MC methods have evolved over the years. Specifically, we consider electron transport calculations by MC, improvements in sampling efficiency afforded by the discrete alias sampling method, and solution of inverse problems by the Symbolic Monte Carlo (SMC) method. As a graduate student, one of us (WLD) used MC to estimate the improvement of cylindrical Geiger-Müller tube efficiency at low energies due to use of a thin coating of high atomic number material on the inside tube surface. Our methods were approximate but the results were reasonably good. We will discuss how discrete alias sampling—introduced in 1974—can improve the sampling efficiency significantly over simple table look-up. Finally, we consider an inverse problem in which the form of the governing probability density function is unknown but desired. We also briefly address matters of perspective on use of MC methods.N. Metropolis, S. Ulam, The Monte Carlo Method, 1949, J. Am. Stat. Assoc. 44, 335–341.

Probabilistic Assessment of Ballooning of Pressure Tube under Severe Accident Conditions

For postulated accident scenario of loss of coolant accident coupled with the failure of emergency core cooling system, the pressure tube will deform due to presence of decay heat. The pressure tube deforms due to creep and this shall ultimately result in a contact with the calandria tube. In this work, the time for this contact to happen is calculated considering the uncertainties in mechanical and thermal material properties of the material. Finite element analysis of temperature distribution in the pressure tube has been carried out considering heat dissipation by conduction, convection and radiation. The source is heat generation due to decay heat of fuel bundles inside pressure tube. The ballooning of the pressure tube material is modelled using the Norton’s creep law. The finite element model is validated using experimental results from literature. As the finite element model is very complex and time intensive, it is difficult to employ the traditional uncertainty propagation methods like Monte Carlo simulations. The uncertainty analysis in this work is performed using Wilk’s method. The time duration when the contact of pressure tube and Calandria tube would happen and the temperature of the pressure tube at that instant is estimated. The results are presented in terms of the 95 percentile values with a confidence of 95 percent. The analysis gives an upper bound to the contact time between pressure tube and Calandria tube during loss of coolant accident condition subject to unavailability of emergency core cooling system.

Multitechnique characterization of secondary minerals near HI-SEAS, Hawaii, as Martian subsurface analogues

Secondary minerals in lava tubes on Earth provide valuable insight into subsurface processes and the preservation of biosignatures on Mars. Inside lava tubes near the Hawaii-Space Exploration and Analog Simulation (HI-SEAS) habitat on the northeast flank of Mauna Loa, Hawaii, a variety of secondary deposits with distinct morphologies were observed consisting of mainly sodium sulphate powders, gypsum crystalline crusts, and small coralloid speleothems that comprise opal and calcite layers. These secondary deposits formed as a result of hydrological processes shortly after the formation and cooling of the lava tubes and are preserved over long periods of time in relatively dry conditions. The coralloid speleothem layers are likely related to wet and dry periods in which opal and calcite precipitates in cycles. Potential biosignatures seem to have been preserved in the form of porous stromatolite-like layers within the coralloid speleothems. Similar secondary deposits and lava tubes have been observed abundantly on the Martian surface suggesting similar formation mechanisms compared to this study. The origin of secondary minerals from tholeiitic basalts together with potential evidence for microbial processes make the lava tubes near HI-SEAS a relevant analog for Martian surface and subsurface environments.

Hydrothermal and entropy generation performance of convergent tubes with various dimple shapes

This paper introduces a comprehensive study on the hydrothermal and entropy generation performance of convergent tubes designed with different dimple shapes. The effects of the dimple shape on the flow characteristics (heat transfer and friction) are investigated using validated computational fluid dynamics (CFD) numerical modelling and simulation tools. Inside convergent tubes with different dimple designs, turbulent flows are subjected to a continuous heat flux of 40 kW/m2. Dimpled tube geometries of different diameter ratios (DR) were built within ANSYS-Fluent software (V2022 R2). Four different dimple shapes were investigated: (a) spherical, (b) cylindrical, (c) conical, and (d) stepped-conical. These dimple shapes were examined to investigate the optimal configuration with the best hydrothermal and entropy generation performance. A comparison is made against the baseline straight smooth tube case. The main performance indicators for comparison are Nusselt number (Nu), friction factor (f), and thermal enhancement factor (TEF), calculated for different Reynolds numbers, Re = 3000 to 40,000, and at different diameter ratios, DR = 1 to 2. In addition, thermal, viscous, and total entropy components, the Bejan number (Be), the enhanced entropy generation ratio (Ns,en), and the irreversibility distribution ratio (φs) are evaluated based on the selected geometrical configurations. The results showed that the dimple shape significantly affects the hydrothermal and entropy generation characteristics of convergent tubes. The best average value of the TEF was attained by convergent tubes with stepped-conical dimple shapes at DR = 1.75, which represents a 7.81% increase over the reference smooth tube (the maximum TEF value is 1.3243 at Re = 3000 and DR = 1.25). Furthermore, the minimum levels of Ns,en were achieved by tubes with stepped-conical dimples, with average reductions of 36.92% over the studied Re range. The study provides valuable insights into the design and optimization of convergent tubes with various dimple shapes for various applications.

Blast wave induced strain measurements in polymers using FBG sensor inside shock tube

Polypropylene and polytetrafluoroethylene (Teflon) have several applications in the aerospace industry and the study of their behaviour in high speed impact events is of great significance. This paper demonstrates the use of FBG sensors for measuring blast wave induced strain in aerospace grade polymer samples inside a Vertical Shock Tube (VST). FBG strain measurement assembly incorporating the polymer test sample and embedded FBG sensor has been designed and developed for suitably mounting it in the driven section of the VST. Experiments are carried out by impacting the polymer samples with blast waves of different peak pressures generated inside VST. PCB pressure transducer is used to record the blast pressure profile in the VST. A systematic study of strain profiles developed in the polymer test samples and their dependence on incident blast wave parameters has been carried out. The strain profiles measured by FBG in both the polymer samples are analysed using FFT and continuous wavelet transform analyses. FEM analysis is carried out using ABAQUS dynamic explicit to simulate the blast wave induced compression in polymers for different blast wave peak pressures and compared with experimental results. The application of FBG sensors to measure blast wave induced dynamic strain inside polymer materials and their capability to withstand the harsh environment of impulse test facilities like shock tubes has been demonstrated.

Experimental study on thermal–hydraulic performance of moist air inside flat tube of two kinds of plate-fin heat exchangers

The plate-fin heat exchanger is the core component of the condensing clothes dryer, which has a significant effect on the performance of the dryer. Two types of plate-fin heat exchangers with different fin structures are proposed to improve the performance of condensing dryers, offset-fin heat exchanger and slit-fin heat exchanger. Experimental investigations are conducted to study the thermal–hydraulic performance of moist air inside flat tube. The heat transfer coefficient and pressure drop of the moist air inside flat tube, the heat transfer rate per unit area, latent heat and sensible heat are compared and analyzed under different experimental conditions. The comparison shows that the offset-fin heat exchanger compared with the slit-fin heat exchanger can increase heat transfer rate per unit area by approximately 15%. Moreover, the comprehensive performance improves by 5%, respectively. Finally, correlations for predicting the Nusselt number and Darcy friction factor inside flat tube are proposed. The values deviate within20% and 10%, respectively. The results provide a design guide for applying plate-fin heat exchangers to condensing dryers.