Tube Diameter Research Articles

SAFE PERFORMANCE OF WORKS IN CONSTRUCTION AND HOUSING AND COMMUNAL SERVICES USING THE ORIGINAL SCAFFOLDING DESIGN

Our development relates to construction, namely scaffolding and scaffolding used when working at height. It is intended for fencing the work area when carrying out various types of work, for example, when performing brickwork from scaffolding. In construction, where safety and efficiency play a crucial role, the correct selection and use of scaffolding are integral to every successful project. We have proposed a patent-protected solution. It is a scaffolding railing consisting of vertical support posts hinged with horizontal crossbars, characterised by the fact that each support post is made in the form of a telescopic connection of pipes of different diameters with the possibility of extending them from each other and is fixed with the help of an existing locking device. The hinge connection of horizontal crossbars with them, except the upper row of such bars that are railing, is made in random order, for example, by attaching a hinge to the upper end of the upper tube of the smallest diameter, and is carried out using additional ring elements mounted on the corresponding telescopic connecting tubes. The inner diameter of each of these annular elements, exceeding the outer diameter of the tube on which it is mounted, is less than the outer diameter of the next subordinate telescopic tube. Thus, it can move only vertically in a telescopic connection within this and above pipes. It makes it possible to support each of the ring elements with horizontal crossbars attached to them under their weight at a certain level of height of the vertical support post, determined by the height of the underlying tube of the telescopic connection. At the same time, the lower horizontal crossbar is hinged to the ring element of the largest diameter, put on the lower tube of the telescopic connection, and rested directly on the working flooring made in the form of a sideboard. The proposed device is not technically complex to implement. Its use increases the workers’ productivity, improves the working conditions, and ensures the safety of various construction works. Keywords: safety, construction, ease of use, prototype, fencing, scaffolding.

Prediction of entrainment fraction in two-phase gas-liquid co-current annular flow-A machine learning approach

Entrainment fraction is a crucial parameter to determine liquid holdup, pressure drop, and dryout in two-phase annular flow. It determines the fraction of liquid flows as liquid droplets in the gas core. Usually, empirical correlations are used to predict entrainment fraction. However, these correlations forecast entrainment fractions with large Mean Absolute Percentage Error (MAPE), especially when one correlation is used to predict entrainment fractions for different operating conditions. For instance, existing models considered in this study predict entrainment with MAPE of as much as 120.7 %. Besides around 40 % and 24 % of data were outside of ±30 % and ±50 % ranges. In the framework of this study, a Deep Neural Network (DNN model) has been developed to predict entrainment fraction in annular flow that is applicable for different operating conditions with good accuracy. The neural network is trained and tested for around 1213 entrainment fraction data points extracted from 7 different literature studies. It covers pressure ranges 0.1–20 MPa, tube diameter 5–32 mm with working fluid- air/water, steam/water, and Freon-113. The developed DNN model predicts entrainment fraction with the lowest MAPE compared to the existing models on unseen 155 data from 6 authors that are not used to train or test the model. Furthermore, only 17.61 % and 30.81 % of data remain outside of ±30 % and ±20% limits respectively whereas these values are at least 35.66 % and 52.86 % for existing models that are examined for comparison here.

Tensile behavior of TOBs bolted T-stub to circular steel tube with Reverse-Channel

The T-stub bolted to Circular Steel Tube strengthened by Reverse-Channel using Thread-fixed One-side Bolts (TOBs) under tension was studied in this paper. Through welding a reverse channel, the regular bolted flat endplate connection could be employed for the steel beam to circular steel tube column. At the same time, the reverse channel also strengthens the tube wall and extends the hole thread length. Four TOBs bolted T-stub to Circular Steel Tube strengthened by Reverse-Channel (CST-RC) specimens were designed and tested under tension. Critical parameters were determined as the outer diameter of the steel tube, the tube wall thickness, and the bolt gauge distance. Test results revealed three typical failure modes: complete yielding of the whale tube wall, thread shear failure, and complete yielding of the whole tube wall with the thread failure. As well as the tube wall thickness could effectively increase the load-bearing capacity of the connection, a larger bolt gauge distance could reduce the connection deformation. Finite Element Models (FEM) were developed to analyze the load carrying mechanism of TOBs bolted T-stubs to CST-RC. The connection deformation contour, the yield line patterns of tube wall, and the stress distribution on the threads were presented. The behavior of TOBs bolted T-stubs to CST-RC was compared to that of TOBs bolted T-stubs to Circular Steel Tube (CST), and that of TOBs bolted T-stubs to Square Steel Tube (SST). It was found that the reverse channel effectively reduces the circular tube wall deformation and increases connection load-bearing capacity.

Influence of Shallow Foundations on the Response of Steel Wind Towers

The objective of this study, concerning the soil–structure interaction of shallow reinforced concrete foundations of wind towers with circular cross-sections, was determination in a closed form of the monotonic moment–rotation curve of the soil–foundation complex. This study was based on elastic and plastic analyses of shallow rigid foundations assuming a Winkler soil type including the flexibility of the foundation in the elastic range and the nature of the soil (cohesive and non-cohesive types) through corrective factors of the constant of the Winkler model. The flexibility of the foundations influences the moment–rotation response through the initial rotational stiffness with a coefficient between 1 and 0.7 for a width-to-span ratio between 5 and 2. The nature of the soil is considered through corrective factors of 0.75 and 1.3 of the Winkler constant for cohesive and non-cohesive soil, respectively. Analyses carried out stressed that a possible design valued to be adopted in a steel wind tower with shallow foundations is a diameter of the steel tube 1/15 of the height of the tower, a diameter of foundation 0.75 of the length, and a depth of foundation 1/10 of the diameter and thickness of steel tower ratio diameter equal to 1/10. In this range it was observed that the effects of the soil-to-foundation interaction in the elastic range influences the critical length in the stability of the steel wind tower, with values between 2.5 and 2 (column fixed at the base) in a range of Winkler constant between 0.1 and 1 daN/cm3. Finally, an experimental validation of the proposed model was carried out with the data available from the literature.

Research on the R513A condensation heat transfer characteristics in horizontal microfin tubes

R513A has been proposed as alternative to R134a due to its lower GWP. So, it is necessary to investigate the condensation heat transfer characteristics and pressure drop of R513A in the horizontal tubes. The 12.70-mm-OD and 9.52-mm-OD tubes were selected for condensation tests. It was found that the R134a condensation heat transfer coefficient in the 12.70-mm-OD microfin tube was similar to the R513A condensation heat transfer coefficient, and the deviation was about −3% ∼ +9%; R513A yielded 4.44% ∼ 16.01% lower pressure drop than R134a. The R513A heat transfer coefficient of the microfin tube was about 1.42–1.74 times of that of the smooth tube, and the pressure drop was 39.11% ∼ 76.63% than that in the smooth tube. Additionally, the condensation heat transfer coefficient and pressure drop of the 9.52-mm-OD test tube were 23.88% ∼ 41.62% and 40.79% ∼ 71.86% higher than those of the 12.70-mm-OD tube, respectively. The micro-fin structure inside the microfin tube resulted in efficient heat transfer, but also increased the fluid flow power consumption. Moreover, as the tube diameter decreased, the effects of sheer stress and surface tension increased. Furthermore, experimental data were also compared with previous correlations proposed for microfin tubes. More experiments are still required to develop more applicable theoretical correlations in future.

Wall confinement effects on the dynamics of cavitation bubbles in thin tubes

Cavitation is a common phenomenon in nature and has numerous applications. In contrast to a cavitation bubble in a free domain, a cavitation bubble in a thin tube is restricted by the tube wall, which is expected to significantly affect bubble evolution, but its mechanism is still unclear. In this study, the dynamics of a cavitation bubble in a thin circular tube is studied by numerical simulation, focusing on the confinement effects of the tube. The results show that besides affecting the size and lifetime of the bubble, the confinement effects of the tube lead to the generation of counter jets and a ring jet during the contraction process of the bubble, and the curvature of the two counter jets determines the ring jet's peak velocity. When the bubble deviates from the midpoint of the tube in the axial direction, the two sides of the bubble along the axial direction show asymmetric behaviors, which results in the bubble migrating toward the midpoint. The tube diameter, tube length, liquid viscosity, and initial bubble position can significantly influence the degree of confinement effects, which can be characterized by the variations of several key indicators, such as bubble size, lifetime, degree of deformation, counter jet velocity, ring jet velocity, and axial migration of the bubble.

Compressive performance of eccentrically double-cell concrete-filled circular steel tubular columns

This paper presents a series of tests conducted on axial compression of concrete-filled steel tubes with double inner circular steel tubes (DIC-CFST) stub columns. The DIC-CFST stub columns are composed of four elements: an outer circular steel tube, two inner hollow circular steel tubes arranged symmetrically along the diameter of the outer tube, and concrete filling the space between the three steel tubes. A total of 27 specimens with varying eccentricity ratio (e), hollow ratio (ψ), and concrete strength (C) were subjected to the tests. The results indicate that under axial compression, noticeable local buckling failures occur in both the inner and outer steel tubes. Concrete failure manifests as vertical through cracks and circumferential crushing zones. The load-deformation curve of the specimens remains essentially the same as that of a full-section concrete-filled steel tube. A general positive correlation exists between the ultimate bearing capacity and the strength of concrete, and the range of eccentricity ratio and hollow ratio significantly influences the relationship between these two parameters and the ultimate bearing capacity of the specimens. As the concrete strength increases, the initial stiffness exhibits a noticeable increase. Conversely, the initial stiffness experiences a significant reduction with an increase in the hollow ratio. The ductility decreases with increasing concrete strength and eccentricity ratio. Furthermore, in comparison to the AISC 360–10 Specification, Eurocode 4, and Han's method, the calculation formula proposed in this paper for determining the ultimate bearing capacity of DIC-CFST stub columns has exhibited superior accuracy.

Optimal standoff distance for a highly focused microjet penetrating a soft material

A needle-free injector using a highly focused microjet has the potential to minimize the invasiveness of drug delivery. In this study, the jet penetration depth in a soft material—which is a critical parameter for practical needle-free injections—was investigated. We conducted jet penetration experiments by varying the inner diameter of the injection tube and the standoff distance between the meniscus surface and the soft material. Interestingly, the results showed that the penetration depths peaked at certain distances from the meniscus, and the positions shifted further away as the inner diameter was increased. By analyzing the velocity distribution of the microjet, the peak positions of the penetration depth and the maximum velocities were inconsistent due to the effects of the jet shape. To account for this, we introduce the concept of the “jet pressure impulse,” a physical quantity that unifies the velocity and jet shape. However, direct estimation of this parameter from experimental data is challenging due to limitations in spatiotemporal resolution. Therefore, we used numerical simulations to replicate the experimental conditions and calculate the jet pressure impulse. Remarkably, the results show that the jet pressure impulse has peak values, which is consistent with the penetration depth. In addition, there is a correlation between the magnitude of the jet pressure impulse and the penetration depth, highlighting its importance as a key parameter. This study underlines the importance of the jet pressure impulse in controlling the penetration depth of a focused microjet, providing valuable insights for the practical use of needle-free injection techniques.

Determination of the Optimum Test Conditions for Measurement of Glucose Level in Liquids

Diabetes is a disease that affects more than 400 million people worldwide and currently lacks a cure. Monitoring blood sugar levels is crucial in minimizing the effects of this disease and protecting against its complications. Invasive and minimally invasive methods are commonly used traditional approaches for detecting and monitoring blood sugar levels. However, these methods bring along psychological and infectious risks. Currently, efforts are being made to develop a non-invasive method for determining blood sugar levels. Microwaves offer the possibility of non-invasive glucose measurement as they do not cause any harmful effects on human tissue. Furthermore, the complex permeability of blood is sensitive to glucose concentration in the microwave band. In literature, most of the studies are done with vector network analyzers (VNA) to detect blood sugar level noninvasively. In this study, an expensive and bulky VNA is replaced by an affordable microwave source and RMS power detector. The influence of the type and diameter of the test tube material used for non-invasive determination of sugar levels is examined with this setup. Additionally, the effect of the distance between the Vivaldi antennas used during measurements and the test tube is investigated. The results indicate that measurements performed using plastic test tubes yield better results compared to glass test tubes. Moreover, reducing the diameter of the test tube leads to improved outcomes. It has been observed that accurate results cannot be obtained if the antennas and the test tube are too close (4.5cm) from each other.

Design and optimization analysis of a new double-layer tube type heat exchanger for lead-bismuth reactors

Double-layer heat tubes have been designed to effectively reduce the occurrence of heat pipe rupture accidents. However, inter-tube thermal contact resistance can decrease heat transfer efficiency, thus hampering the heat dissipation in the primary loop system of lead-bismuth reactors. Therefore, optimizing the design of double-layer heat tubes is necessary. This work focuses on the double-layer heat exchanger of a lead-bismuth reactor and utilizes gallium-based graphene nanofluids as a thermal interface material to fill the gap between the heat tubes. Furthermore, the impact of the length, wall thickness, outer diameter, and spacing of heat tubes on the heat transfer performance of the double-layer heat exchanger with and without the nanofluids has been analyzed. The study aims to optimize the JF factor and cost-effectiveness ratio (CER). Genetic algorithms are employed to optimize and evaluate the heat transfer performance of the main heat exchanger based on the four aforementioned parameters. Consequently, a new design scheme is obtained for the double-layer heat exchanger, which increases the optimized overall heat transfer coefficient of the main heat exchanger by 5.79%, pressure drop in the primary loop by 2.32%, JF factor by 5%, and CER by 24.62%. These results demonstrate that the gallium-based graphene nanofluids can effectively enhance the heat transfer performance of the double-layer heat exchanger while reducing the likelihood of steam generator tube rupture accidents.

Protective effect of dental pulp stem cells' conditioned medium against cisplatin-induced testicular damage in rats

Cisplatin is a highly effective chemotherapy drug used to treat most solid tumors. However, one of its side effects is testicular toxicity, which can lead to fertility abnormalities. This study investigated the effectiveness of dental pulp mesenchymal stem cells conditioned medium (DPSC-CM) on cisplatin-induced testicular toxicity. In this study, 36 eight-week-old male Wistar rats were randomly divided into three groups equally (n = 12). Group 1 control "CTR", which received normal saline (0.5 ml) intraperitoneally (i.p), group 2 "Cis" which received an intraperitoneal dose of cisplatin (7 mg/kg), and group 3 "Cis+CM" which received an i.p injection of DPSC-CM (0.5 mg/kg) after cisplatin injection. Biochemical, histomorphometric, and histopathological studies were performed on the testis. Our results exhibited that cis administration led to a decline in total body weight, testis weight, diameter, and volume. A decrease in testosterone and IL-6 serum levels, as well as a decrease in IL-6 and TNFα levels, the activity of catalase and SOD enzymes, and an increase in MDA in testicular tissue were detected. Testicular tissue damage was associated with a significant decrease in tube diameter, germinal epithelium height, number of spermatogonia and Sertoli cells, along with a noticeable increase in basement membrane thickness, and perivascular fibrosis. DMSC-CM improved all the mentioned parameters. Taken together, our results demonstrated that DMSC-CM due to its antioxidant and anti-inflammatory properties, could be effective in reversing cisplatin-induced testicular toxicity.

Experimental and numerical investigation on the mechanisms of novel heat transfer deterioration of supercritical CO2 in vertical tubes

Understanding the mechanisms of supercritical CO2 heat transfer deterioration (HTD) has significant importance for ensuring the safety and reliability of supercritical Brayton cycles. Therefore, the effects of mass flux, wall heat flux, and tube diameters on the heat transfer characteristics of supercritical CO2 inside vertical tubes are studied using experimental and numerical methods. Results indicate that the heat transfer performance is positively influenced by an increase in mass flux and heat flux, as well as a decrease in tube diameter. When HTD occurs, the overall heat transfer performance is indeed significantly compromised. When the bulk fluid temperature exceeds Tpc, the thermal acceleration effect amplifies the mainstream velocity, stabilizing the Kelvin-Helmholtz instability between the pseudo-two-phases, thereby causing a new type of HTD that is named Type II HTD in this paper. The so-called post-dryout HTD occurs when the bulk temperature surpasses T+, causing a complete transition from pseudo-liquid to pseudo-gas state and resulting in a pseudo-single-phase flow. The heat transfer capability of the low-density and low-thermal-conductivity pseudo-gas diminishes as the temperature rises, leading to post-dryout HTD. The present work explains the mechanisms of two types of HTD and highlights the similarities between subcritical boiling and supercritical pseudo-boiling flow structures. This study also establishes a theoretical foundation for understanding pseudo-two-phase flow patterns during pseudo-boiling.

Numerical and experimental investigation of the flow and heat transfer characteristics for cold storage heat exchanger

Decreasing the freezing time of the cold storage heat exchanger was an effective way to reduce the risk of cold chain breakage and the fluctuation of cold chain temperature. A validated unsteady mathematical model of the cold storage heat exchanger was established to analyze the transient evolution of temperature, velocity, ice distribution, and heat transfer coefficient for different diameters of heat transfer tubes and coolant temperatures. The results showed that there were four stages of temperature in the cold storage heat exchanger, namely the primary cooling stage, the freezing stage, the secondary cooling stage, and the constant temperature stage. The ice fraction distribution and the heat transfer coefficient were inextricably linked to the water's natural convection. The average heat transfer coefficient decreased with decreasing coolant temperature and increasing heat transfer tube diameters. The freezing time decreased with the coolant temperature and the diameter of the heat transfer tubes decreasing. The tendency of the inhomogeneity of ice distribution first increased with the ice fraction up to 0.75 and then decreased with the ice fraction over 0.75. The inhomogeneity decreased with the coolant temperature increasing when the diameter of the heat transfer tubes was greater than 2 mm.

Improvement of Formability in Parallel Double-Branched Tube Hydroforming Combined with Pre-Forming and Crushing Processes.

In hydroforming of parallel double-branch tubes, the material entering the branch zone is obstructed by material accumulation in the main tubes and corners, which decreases the branch height. A tube hydroforming approach is combined with pre-forming and crushing (THPC) to mitigate this problem. A larger diameter tube blank is flattened for pre-forming and then subjected to radial compression for crushing. In the next step, hydroforming forms the parallel double-branch tubes. Experiments and numerical simulations are then carried out to analyze the effect of traditional tube hydroforming (TTH) and the proposed THPC process on the formability of parallel double-branch tubes. The results show that for tubes obtained via THPC, the tube burst pressure increases by 27.5% and the branch height increases 2.37-fold compared to TTH. Additionally, the flattening, pre-forming, and crushing stages cause work hardening of the tube when using the TPHC process. Flattened tubes undergo radial compression to improve the material flowing into the branch tube. The formability of parallel double-branched tubes can be improved by using the TPHC process. Consequently, tube hydroforming, combined with pre-forming and crushing, has been confirmed as a feasible forming process for fabricating parallel double-branch tubes.

Design and Technoeconomic Analysis of Fischer–Tropsch Fixed‐Bed Synthesis with Cobalt‐Based Catalysts

A multitubular Fischer–Tropsch (FT) reactor with gas recycle and a cobalt‐based catalyst is simulated by a 2D fixed‐bed model that considers the complex kinetics, all relevant mass and heat transfer aspects, and also the influence of the changing molar flow rate by the FT reaction, of pressure drop, and of formation of steam, which decreases the reaction rate of FT synthesis. Optimal values of gas velocity and single‐tube diameter and length are determined by a technoeconomic analysis. The comparison of the data of the FT reactor modeled in this work with data of commercial reactors indicates that the used model reflects reality well and is reliable. A superficial gas velocity of 0.5 m s−1, a tube diameter of 3 cm, and a length in a range of 12–20 m are appropriate for a high production rate of C2+‐hydrocarbons with minimal operating costs of the FT unit, even for a large range of the electricity price from 0.06 to 0.3 € kWh−1.

Flexural behavior of circular rubberized concrete-filled double-skin steel tubular beams: Experiments

The study aims to assess the impact of RuC on twelve concrete-filled double-skin steel tube (CFDST) specimens. The research explores key variables, including outer tube slenderness ratio, hollow ratio, and rubber replacement ratio. Rubber particles replace natural aggregates at replacement ratios (ρνr) of 0%, 15%, and 30% by mass. The experimental findings are comprehensively discussed, encompassing member flexural capacity, confinement effects, ductility, energy dissipation, and failure mechanisms. The findings reveal that replacing normal concrete (NC) with RuC leads to a reduction in beam flexural strength ranging from 5.0% to 18.1%, depending on ρνr and outer tube diameter. In contrast, RuC members exhibit an increase of up to 70% in ductility and 27.7% in energy dissipation compared to members with NC, depending on rubber content. Increasing the outer tube thickness proves to be an effective method for mitigating strength reduction due to rubber replacement. Specifically, elevating the outer tube thickness from 3.6 mm to 4.5 mm results in strength enhancements of 17.0%, 19.0%, and 23.7% for beams with NC, 15%RuC, and 30%RuC, respectively. Furthermore, the results are applied to assess existing design models and to suggest modifications that offer improved strength estimations for a broad spectrum of rubber replacement ratios.

Collective radial breathing modes in homogeneous nanotube bundles

We present a Raman study of the collective vibrations arising from the homogeneous bundling of single-walled carbon nanotubes and analyze the dependence of their vibrational coupling on the tube diameter using two systems, single-walled carbon nanotube coils and a monochiral carbon nanotube film. We report on two breathing-like modes for quasi-infinite bundles, compared to the single radial breathing mode characteristic for isolated tubes. The exciton-phonon coupling in these modes is probed with resonant Raman spectroscopy, revealing the same resonance energy for both breathing-like peaks. Our experimental findings align well with previously reported theoretical studies, demonstrating a 1/d scaling for all modes, as well as confirming the relative shift of the modes dependent on intertube interaction. These vibrations provide insight into the role of intertube lattice dynamics in two-dimensional THz-range phononic crystals.

Prediction of optimal dimensions and arrangements of circular tubes of a fin and tube heat exchanger for an improved thermal-hydraulic performance

In the present work, the thermal-hydraulic performance of a fin and tube compact heat exchanger (FTHE) with different spatial arrangements of tubes and variations of tube diameter is investigated numerically. The three types of spatial arrangement of the tubes, namely inline, staggered row (SR), and staggered column (SC) arrangements, and five different tube diameters starting from Dc = 6.51 mm to Dc = 10.51 mm considered with a constant increment of 1 mm, are investigated for the augmentation of the heat transfer. The entire analysis is conducted under the low inlet velocity ranging from 0.7 m/s to 1.1 m/s. The results indicate that FTHEs (flow-through heat exchangers) have better thermal-hydraulic performance when arranged in staggered column configurations compared to inline and staggered row arrangements. However, it was observed that the pressure drop increased in staggered column arrangements compared to inline and staggered row arrangements. The performance ranking method MOORA is applied to optimize the spatial arrangements of tubes. The study’s findings suggest that the performance of FTHE is better in the case of staggered column arrangements, which offer a fair agreement with performance evaluation criteria (PEC3 = Q/(Pf +Pp )). After achieving the staggered column arrangement as an optimum spatial arrangement of the tubes, the influence of tube diameter on the performance of FTHEs is investigated for this arrangement only. The findings indicate that when the tube diameter is increased, there is a corresponding increase in both the characteristics like heat transfer coefficient and the pressure drop penalty. The performance ranking method MOORA is applied to get an optimum tube diameter, which is cross-checked by the TOPSIS method. Based on PEC3 and two optimization approaches, MOORA and TOPSIS, it is revealed that a larger tube diameter leads to better overall performance of the FTHEs.

Nonlinear finite element and machine learning modeling of tubed reinforced concrete columns under eccentric axial compression loading

There is still insufficient data on the behavior of tubed-reinforced concrete columns (TRCCs) under the eccentric compression. Thus, this research work comprehensively examines the eccentric compression behavior of TRCCs using nonlinear finite element modeling and machine learning (ML). To do this, numerical simulation and parametric analysis based on existing investigations were conducted. In addition to the existing 22 specimens with limited test variables, additional 188 specimens were developed to cover a wide range of parameters, including the load eccentricity, transverse reinforcement spacing, columns’ slenderness ratio, yield strength of steel, and outer steel tube diameter. Additionally, six ML models were created to estimate the ultimate load results. The results indicated that increasing the outer steel tube yield strength and diameter, and reducing the load eccentricity, slenderness ratio, and spacing of the transverse reinforcement enhanced the load-carrying capacity of the columns. The Gaussian process regression model demonstrated superior performance metrics in comparison to other ML models, with the highest R2 values (0.998613 in training and 0.99823 in testing stages) and lowest root mean square error values (0.007213 in training and 0.008471 in testing stages). To save money, time, and resources compared to laboratory testing, an online-based prediction program is finally presented to predict the columns’ ultimate load.

Design of an improved impedance tube to measure sound absorption coefficients of flexible textile materials

Textile materials have demonstrated significant potential in sound noise reduction due to their porous, lightweight, and easily processed nature. However, the current experimental setup for measuring the sound absorption of small-sized samples is expensive. Additionally, there is a lack of suitable equipment for measuring the sound absorption of flexible textiles as it is challenging to mount flexible samples into an impedance tube. This paper presents the design, fabrication, and testing of impedance tubes specifically designed for measuring the sound absorption coefficients of textile materials. The impedance tubes were designed based on the transfer function and two-microphone methods, with diameters of 100 mm and 30 mm. These tubes covered frequency ranges from 200–1600 Hz and 500–6400 Hz, respectively. Furthermore, improved sample holders were developed to mount flexible textile materials without altering the acoustic impedance characteristics of the front surface of the test sample. Validation experiments were conducted on melamine foams, and the results were compared with those obtained from the commercial B&K 4206 setup. The results obtained from the designed setup showed good agreement with those from the B&K 4206 system. The maximum error observed was 8% at 2800 Hz for the 30 mm diameter tube and 8.3% at 1600 Hz for the 100 mm diameter tube. Finally, the designed system was used to measure the sound absorption coefficients of textile materials with varying densities. The results obtained were consistent with the material properties, demonstrating the effectiveness of the designed setup.