Airflow Measurements Research Articles

Endonasal Thermal Imaging Before and After Nasal Airway Surgery.

Nasal airway surgery is often applied when treatment fails to relieve nasal obstruction. However, surgery that improves airflow does not always alleviate the symptoms of nasal obstruction. The perception of nasal breathing is likely more related to changes in mucosal temperature than the mechanical sensation of flow or pressure. This study aims to measure intranasal mucosal temperature pre-and post-surgery using endonasal thermal imaging, exploring its correlation with subjective nasal breathing and objective airflow measurements. A prospective study of adult patients with nasal obstruction managed with nasal airway surgery was performed. Intranasal mucosal temperatures were determined using the thermal endonasal image of the nasal passage produced by the infrared radiometric thermal camera (FILR VS290). A comparison was made between the mean values of mid-expiration (ExT) and mid-inspiration (InT) temperature data (internal nasal valve, nasal cavity, inferior turbinate, and overall airway [mean value]) and visual analog scale (VAS), Nasal Obstruction Symptom Evaluation (NOSE) scale and nasal airway resistance (NAR) before and after surgery. Seven patients (35.14 ± 16.45 years, 57.14% female) were included. All NOSE, VAS, and NAR improved after surgery (59.29 ± 10.89 vs 17.14 ± 14.64; P < .001, 64.50 ± 26.79 vs 18.57 ± 19.99; P < .001, 0.82 ± 0.48 vs 0.34 ± 0.11 Pa/cm3/s; P = .002, respectively). ExT, InT, and the difference between ExT and InT of three areas and overall airway were similar between pre-and post-surgery. No statistically significant correlations were found between intranasal mucosal temperature, VAS, NOSE, and NAR at pre-and post-surgery except for the difference between ExT and InT of overall airway and NOSE pre-operative (Pearson r = 0.57; 95% CI 0.06-1.09; P = .03). Endonasal thermal imaging can assess the intranasal mucosal temperature of a patient. However, more precise imaging of the nasal passages and data acquisition are required to establish mucosal temperature as an objective measure of nasal obstruction before and after nasal airway surgery in a clinical setting.

3D-3C measurements of flow reversal in small sessile drops in shear flow

Sessile drops play an important role in nature and the operation of many technical and biological systems as for instance fuel cells, cleaning processes, lab-on-a-chip devices and single-cell analysis. Nonetheless, their dynamic behaviour in a shear flow is still not fully understood (e. g. detachment mechanism). Challenges exist regarding the precise simulation of two-phase flows as well as difficulties in conducting flow measurements with sufficient temporal resolution of more than 1 kHz. In this article, we present the first three-dimensional flow measurements in strongly oscillating drops stemming from a shear flow by using a monocular 3D localization microscope based on a Double-Helix Point Spread Function combined with Particle Tracking Velocimetry. The high temporal resolution and the large measurement volume - in terms of microscopy - make it possible to measure the time- and phase-averaged flow in small drops with Bond numbers (Bo) smaller than 1. Water drops were placed in an air flow channel and measurements were conducted for Reynolds numbers (Red) from about 750 to 1700. Our measurements show that the results of previous investigations for drops with Bo>1 concerning vortex pattern and flow reversal inside the drop apply for smaller drops as well. In addition, we are able to reveal the three-dimensional flow structure and multiple vortex-pattern in time and space. We discover a periodic 3D vortical flow pattern that corresponds to the first and second eigenfrequency of the drop. Moreover, we demonstrate the potential of adaptive optics to correct measurement errors stemming from time-varying light refraction when conducting measurements through the fluctuating drop surface, in particular for opaque substrates. The results may help in understanding the coupling of inner and outer flow for sessile drops in shear flow which allows for an analysis of the onset motion of these drops, i.e. drop removal. Removal of sessile drops plays a crucial role in many applications, which includes among other things the water management of fuel cells where small drops with Bo<1 predominantly occur.

Flexible curved multi-functional sensors for air flow and vibration signal measurement of train bogie

Abstract The fluid-solid coupling effects with the aerodynamic noise and structural vibration signal have great part in measurement accuracy and fault diagnosis of the train bogie. It is important to collect aerodynamic noise and structural vibration data for safety evaluation and on-line structural health monitoring (SHM) of the bogie, which brings new challenges to the integration and installation of the sensors in the limited space and complicated operation condition of the train bogie. Flexible curved multifunctional sensors (FCMFS) integrated with the hot film and structural vibration sensor units is designed to the air flow and structural vibration measurement of the train bogie. Bogie vibration and wind tunnel test platforms with FCMFS are built to the air flow velocity and vibration data measurement on the bogie surface under different operation conditions. Piezoelectric Polyvinylidene fluoride(PVDF) sensors have significant output in the wind tunnel and vibration experiments, and the hot film sensor is only sensitive to the air flow signal. The effect of vibration signal to the hot film sensor could be ignored, which is applied to decouple the aerodynamic noise and structural vibration signals for improving the measurement accuracy of the train bogie. The dynamic performance of FCMFS is verified in Rail Transmit Base of East China Jiaotong University, which is applied to SHM and rapid fault diagnosis of train bogie. The air flow distribution and vibration data are collected to safety assessment and fault diagnosis of train bogie, which would promote the intelligent maintenance level of the train bogie.

Exploring the Relationships Between Clinical Examination Findings, Subjective Reported Symptoms and Objective Nasal Patency Measures in Nasal Obstruction: A Baseline NAIROS Sub-Study Analysis.

The role of objective nasal airflow measures using peak nasal inspiratory flow (PNIF) and rhinospirometry in supporting clinical examination findings when offering patients septoplasty remain undefined. To explore the baseline relationships between clinical examination findings, subjective reported symptoms and objective nasal patency measures in nasal obstruction. This is a sub-study of the NAIROS trial. Participants with nasal obstruction secondary to septal deviation were included in this NAIROS sub-study. The side of septal deviation, enlargement of inferior turbinate (IT), the need for IT reduction if septoplasty was being performed, the area of septum deflecting into the airway and observer rated airway block (ORAB-arbitrarily divided by <50% and >50% blockage) were assessed by clinicians. The subjective score of nasal obstruction was assessed using the Double Ordinal Assessed Subjective Scale (DOASS). Objective nasal patency measures (e.g., nasal partitioning ratio, [NPR] and PNIF) were measured using PNIF and rhinospirometry. The mean NPR for left-sided, both-sided and right-sided septal deviation was -0.35, -0.02 and 0.51, respectively (p < 0.001). There was very weak correlation between the requirement for IT reduction and PNIF change (0.13, p < 0.01). There was no difference in mean PNIF (94 L/min vs. 93 L/min) and mean DOASS (0.33 vs. 0.38) for participants with ORAB rated <50% and >50%. The mean NPR for participants with ORAB >50% was higher than for those with ORAB <50% (0.51 vs. 0.41, p = 0.002). There was strong correlation between the DOASS and NPR (+0.737, p < 0.001). The mean DOASS score for right-sided, both-sided and left-sided septal deviation was 0.32, 0.05 and -0.29, respectively (p < 0.001). This study identified strong relationships between the clinician rated side of septal deflection, the patient reported DOASS and the objective NPR measurements. NPR and the clinician rated degree of airway blockage were concordant.

Development and experimental evaluation of an acoustic flow meter prototype for measuring air flow

This study outlines the development and testing of a flow meter prototype specifically designed for use in nuclear reactor environments. The meter uses flow-induced vibration to measure flow rates and is designed for remote monitoring in harsh environments where radiation can damage electronics. The device generates a vibration signal produced by a feedback system when fluid flows out of an orifice and interacts with a downstream wedge. The frequency of the vibration signal corresponds directly to flow rate and velocity. The study investigates geometric parameters intrinsic to the prototype, such as orifice height, width, edge distance, and chamber length. Different configurations were also tested, including a bypass loop with variable cross-sections around the device. The investigation results reveal the impact of these geometric parameters on the vibration signal output, providing valuable insights for future design improvements and enhancing the effectiveness of flow metering systems used in nuclear reactor applications.

Research on Intelligent Ventilation System of Metal Mine Based on Real-Time Sensing Airflow Parameters with a Global Scheme

In ventilation systems of metal mines, the real-time measurement of the airflow field and a reduction in pollutants are necessary for clean environmental management and human health. However, the limited quantitative data and expensive detection technology hinder the accurate assessment of mine ventilation effectiveness and safety status. Therefore, we propose a new method for constructing a mine intelligent ventilation system with a global scheme, which can realize the intelligent prediction of unknown points in the mine ventilation system by measuring the airflow parameters of multiple known points. Firstly, the nodal wind pressure method combined with the Hardy–Cross iterative algorithm is used to solve the mine ventilation network, and the airflow parameters under normal operation and extreme working conditions are simulated, based on which an intelligent ventilation training database is established. Secondly, we compared the airflow parameter prediction ability of three different machine learning models with different neural network models based on the collected small-sample airflow field dataset of a mine roadway. Finally, the depth learning method is optimized to build the intelligent algorithm model of the mine ventilation system, and a large number of three-dimensional simulation data and field measurement data of the mine ventilation system are used to train the model repeatedly to realize the intelligent perception of air flow parameters of a metal mine ventilation network and the construction of an intelligent ventilation system. The results show that the maximum error of a single airflow measurement point is 1.24%, the maximum overall error is 3.25%, and the overall average error is 0.51%. The intelligent algorithm has a good model training effect and high precision and can meet the requirements of the research and application of this project. Through case analysis, this method can predict the airflow parameters of any position underground and realize the real-time control of mine safety.

Super-resolution for Gas Distribution Mapping

Gas Distribution Mapping (GDM) is a valuable tool for monitoring the distribution of gases in a wide range of applications, including environmental monitoring, emergency response, and industrial safety. While GDM is actively researched in the scope of gas-sensitive mobile robots (Mobile Robot Olfaction), there is a potential for broader applications utilizing sensor networks. This study aims to address the lack of deep learning approaches in GDM and explore their potential for improved mapping of gas distributions. In this paper, we introduce Gas Distribution Decoder (GDD), a learning-based GDM method. GDD is a deep neural network for spatial interpolation between sparsely distributed sensor measurements that was trained on an extensive data set of realistic-shaped synthetic gas plumes based on actual airflow measurements. As access to ground truth representations of gas distributions remains a challenge in GDM research, we make our data sets, along with our models, publicly available. We test and compare GDD with state-of-the-art models on synthetic and real-world data. Our findings demonstrate that GDD significantly outperforms existing models, demonstrating a 35% improvement in accuracy on synthetic data when measured using the Root Mean Squared Error over the entire distribution map. Notably, GDD appears to have superior capabilities in reconstructing the edges and characteristic shapes of gas plumes compared to traditional models. These potentials offer new possibilities for more accurate and efficient environmental monitoring, and we hope to inspire other researchers to explore learning-based GDM.

An exploratory study on bamboo permeability for evaluation of treatability with chemical solutions

The rapid and uniform impregnation of resins and preservative fluids is critical to improving the quality and durability of wood-based materials. Permeability coefficients obtained in laboratory experiments aid in the development of optimal conditions for uniform resin filling on an industrial scale. However, due to the shape and orientation of pores in the bulk structure of bamboo, simplified permeability equations may not be sufficient to provide realistic resin impregnation predictions. In this study, the permeability coefficients for Dendrocalamus asper bamboo were determined using air flow measurements and Forchheimer's equation in the x, y, and z directions, and they were correlated to the bamboo microstructure, providing a detailed perspective on how to further investigate this property for real-world applications, such as pressure treatments with chemical solutions. Porosity was measured using mercury intrusion porosimetry (MIP) and water immersion methods to aid in the permeability analysis. The results showed that the longitudinal direction had 1000 to 10,000 times higher permeability coefficients than the radial and tangential directions. This finding is consistent with the alignment of transport vessels as well as the limited pore network in the transversal bamboo section. The outer region of bamboo had higher radial permeability than the middle and inner layers, despite having lower porosity. It is hypothesized that the greater number of vessels, albeit smaller, provides a more direct path for air to flow. The Darcian permeability coefficients of bamboo were found to be comparable to those reported in the literature for wood. This exploratory study provided insights into a novel approach for assessing the treatability of bamboo species.

A New Method for Evaluating the Homogeneity within and between Weave Repeats in Plain Fabric Structures Using Computer Image Analysis.

This article introduces a novel, rapid, and non-destructive method for assessing homogeneity within and between weave repeats in fabric structures, termed intra-repeat (IAR) and inter-repeat (IER) evaluation. The method focuses on structural parameters, including inter-thread pores (ITPs) and warp and weft pitches, using computer image analysis. Each parameter is assigned to a module in the repeat weave pattern, facilitating the sorting of modules in the IAR and IER fabric structure arrangement. The method was verified using artificial images and 30 real plain fabrics with varying degrees of warp grouping, employing the author's proprietary software, MagFABRIC version 2.1The general measurable coefficients of intra- and inter-homogeneity were defined and related to the airflow measurements of these fabrics. Multiple regression models of airflow revealed strong dependencies, particularly for F = 10, with the size, shape, and position of ITPs and warp and weft pitches showing significant correlation. These findings underscore the importance of the new homogeneity parameters in textile structure analysis, including both IAR and IER woven fabric structure homogeneity parameters. The research aims to model specialized fabrics (e.g., barrier, filtration, composite fabrics) to address local changes in fabric structure affecting properties such as filtration efficiency, air permeability, and mechanical properties, especially in applications like composites or medical implants.

Numerical simulation and experimental study of aluminum heat exchanger based on Comsol Multiphysics

Controlling the temperature of the air flow during printing can greatly improve the data measurement of air flow and the printing effect of selective laser melting equipment. In this study, an aluminum-welded heat exchanger was designed and manufactured combined with an engineering application example. The thermal performances of heat exchanger were carried out by experiment and numerical simulation in Comsol Multiphysics. Results show that the model has high accuracy (the relative error is less than 12% in most cases and the absolute error is less than 16 Pa below the flow rate of 350 m3/h), and the overall pipeline resistance loss is small. The temperature difference between outlet and inlet is always lower than 6.5 °C during actual working conditions, which meets the requirements for use. The research can provide good theoretical guidance for the design and application of aluminum heat exchangers.

Acoustic travel time tomography for simultaneous indoor air temperature and airflow measurements

Acoustic travel time tomography for simultaneous indoor air temperature and airflow measurements

Monitoring air fluxes in caves using digital flow metres

Precise measurements of airflow within caves are increasingly demanded to assess heat and mass transfers and their impacts on the karst environment, including subsurface ecosystems, hydrochemistry of karst water and secondary mineral precipitates. In this study, we introduce a new, low-cost and lightweight device adapted to monitoring air fluxes in caves which addresses the need for reliable measurements, low power consumption, durability and affordability. The device was calibrated in a wind tunnel, showing the high accuracy and precision of the device. Field-related uncertainties were further investigated in a ventilated cave to determine the effect of local airflow conditions on the inferred mass flux. Comparing measured values with a 3-D air velocity distribution modelled on a surveyed cave section suggests that most of the uncertainties in estimating the airflow result from the relative position of the instrument in the streamlines rather than from the accuracy of the device.

Numerical simulation analysis and experimental verification of air flow measurement in large-diameter S-shaped pipe

Abstract The ventilation systems in nuclear power plants, hydropower plants, and other large-scale projects involve the transportation of fluids through large-scale pipelines. To achieve a more stable flow velocity distribution, the fluid needs to pass through a straight pipe section of sufficient length upon entering the pipe. Typically, this straight pipe section should be at least 15 times the inner diameter of the pipe. However, for large-diameter irregular square pipes with a diameter exceeding 1m, where the curved section is short and there are no long straight pipe sections before and after it, the flow field inside the pipe becomes complex, requiring accurate measurement of the flow rate.In this regard, a numerical simulation analysis is conducted to address this challenge. A mean velocity evaluation method based on the coefficient of variation is proposed. This method identifies multiple points within the pipe that best represent the average flow velocity, determining the insertion depth of sensors and the weight coefficients of these multiple measuring points. A calculation formula is derived, utilizing the cross-sectional average velocity as a function with the velocity values at multiple points in the flow field as independent variables. To validate the accuracy of the proposed method, flow measurement experiments are performed on a wind tunnel test bench. The calculated values obtained from the derived formula through numerical analysis are compared with the experimental results. The relative error within the full range is found to be less than 0.54%, confirming the accuracy of the formula. The research findings present a novel measurement method for airflow in large-diameter irregular square pipes and offer valuable practical insights for engineering applications.

A non-invasive method to monitor respiratory muscle effort during mechanical ventilation.

This study introduces a method to non-invasively and automatically quantify respiratory muscle effort (Pmus) during mechanical ventilation (MV). The methodology hinges on numerically solving the respiratory system's equation of motion, utilizing measurements of airway pressure (Paw) and airflow (Faw). To evaluate the technique's effectiveness, Pmus was correlated with expected physiological responses. In volume-control (VC) mode, where tidal volume (VT) is pre-determined, Pmus is expected to be linked to Paw fluctuations. In contrast, during pressure-control (PC) mode, where Paw is held constant, Pmus should correlate with VT variations. The study utilized data from 250 patients on invasive MV. The data included detailed recordings of Paw and Faw, sampled at 31.25Hz and saved in 131.1-second epochs, each covering 34 to 41 breaths. The algorithm identified 51,268 epochs containing breaths on either VC or PC mode exclusively. In these epochs, Pmus and its pressure-time product (PmusPTP) were computed and correlated with Paw's pressure-time product (PawPTP) and VT, respectively. There was a strong correlation of PmusPTP with PawPTP in VC mode (R² = 0.91 [0.76, 0.96]; n = 17,648 epochs) and with VT in PC mode (R² = 0.88 [0.74, 0.94]; n = 33,620 epochs), confirming the hypothesis. As expected, negligible correlations were observed between PmusPTP and VT in VC mode (R² = 0.03) and between PmusPTP and PawPTP in PC mode (R² = 0.06). The study supports the feasibility of assessing respiratory effort during MV non-invasively through airway signal analysis. Further research is warranted to validate this method and investigate its clinical applications.

Investigation of Ventilation Performance to Improve the Indoor Air Quality of Institutional Kitchens

Indoor Air Quality (IAQ) is a significant health determinant in the building environment. Ventilation plays a significant role in providing comfortable working conditions and securing contaminant removal from indoor spaces. The heat and effluents generated by cooking activity need to be exhausted from the kitchen space to control the IAQ and provide thermal comfort. The study investigates the ventilation performance concerning IAQ of five institutional kitchens in an educational campus. This study evaluates the influence of building parameters on ventilation performance and IAQ using experimental research and Computational Fluid Dynamics (CFD). The empirical part includes field measurement of indoor airflow and IAQ indicators (particulate matter, CO2, temperature, and RH). The Integrated Environmental Solutions Virtual Environment (IESVE) software performs the CFD analysis. The 'Local Mean Age of air' (LMA) is used as a parameter to analyze IAQ. The findings reveal that the LMA reduces with increased cross-ventilation at the operational level and the presence of local exhaust ventilation, such as chimneys. Moreover, a higher slenderness ratio, lower aspect ratio, and lower building volume reduce the age of air.

RPAS operations in urban airflow: Efficient modelling of representative wind speed variations along a flight path through a flow field with changing turbulence characteristics

For remotely piloted aircraft systems (RPAS) operating in the urban environment, the flight path will most likely pass through the turbulent airflow of building wakes. To attenuate or reject instabilities caused by the turbulent airflow, control systems strategies are being developed in preparation for increased demand on the smaller urban air mobility vehicles. In this paper, results from urban airflow measurements of four 1:300 scaled Canadian city model flow fields are examined to provide detailed understanding of flow characteristics that can be found in typical Canadian cities. The results show common patterns for the range of inner city wind speed and turbulence intensity but that within the urban boundary layer (UBL) the variation of flow characteristics does not have a gradient with respect to altitude and that flow characteristics are highly variable along representative flight paths. For the purpose of simulation of RPAS response to the complex urban airflow, methods for using real urban flows data as inputs to simulations is presented. Demonstration of an Advancing Fourier Series (AFS) method, using the measured city data, shows successful preservation of the spatial- and temporal-correlations for reconstruction of a flow time series offering a novel, efficient and flexible approach for implementation of a time-based simulation of RPAS response in complex flow environments such as the urban environment.

Effects of Mucosal Decongestion on Nasal Aerodynamics: A Pilot Study.

Mucosal decongestion with nasal sprays is a common treatment for nasal airway obstruction. However, the impact of mucosal decongestion on nasal aerodynamics and the physiological mechanism of nasal airflow sensation are incompletely understood. The objective of this study is to compare nasal airflow patterns in nasal airway obstruction (NAO) patients with and without mucosal decongestion and nondecongested healthy subjects. Cross-sectional study of a convenience sample. Academic tertiary medical center. Forty-five subjects were studied (15 nondecongested healthy subjects, 15 nondecongested NAO patients, and 15 decongested NAO patients). Three-dimensional models of the nasal anatomy were created from computed tomography scans. Steady-state simulations of airflow and heat transfer were conducted at 15 L/min inhalation rate using computational fluid dynamics. In the narrow side of the nose, unilateral nasal resistance was similar in decongested NAO patients and nondecongested healthy subjects, but substantially higher in nondecongested NAO patients. The vertical airflow distribution within the nasal cavity (inferior vsmiddle vssuperior) was also similar in decongested NAO patients and nondecongested healthy subjects, but nondecongested NAO patients had substantially less middle airflow. Mucosal cooling, quantified by the surface area where heat flux exceeds 50 W/m2, was significantly higher in decongested NAO patients than in nondecongested NAO patients. This pilot study suggests that mucosal decongestion improves objective measures of nasal airflow, which is consistent with improved subjective sensation of nasal patency after decongestion.

Synergistic Effect of Manually Assisted Cough During Mechanical Insufflation-Exsufflation in Patients With Spinal Cord Injury.

Mechanical insufflation-exsufflation (MI-E) and manually assisted cough are frequently employed cough augmentation methods for enhancing cough efficiency in individuals with cervical spinal cord injury (CSCI). This study aimed to evaluate the synergistic impact of combining manually assisted cough and MI-E on cough peak flow in subjects with CSCI and identify their related factors. Fifteen subjects with CSCI with cough peak flow > -270 L/min underwent 5 consecutive days of 5 cough augmentation sessions; cough peak flow during exsufflation and the total insufflation volume (TIV) during insufflation were measured. Only MI-E was administered on days 1 and 5, whereas on days 2-4 one MI-E-only session followed by 3 MI-E and manually assisted cough sessions was implemented followed by a fifth MI-E-only session. The cumulative and carry-over effects of increasing treatment sessions and any associated factor on cough peak flow during MI-E-assisted coughing were assessed using a linear mixed model (LMM) with repetitive air-flow measurements within the same participants. No cumulative or carry-over effects of manually assisted cough and MI-E were shown with the accumulation of treatment days or sessions. The LMM confirmed that using manually assisted cough (-0.283 L/s, P < .001), TIV (-0.045 L/s, P = .002), and the individual manually assisted cough variance (-0.022 L/s, P = .01) significantly influenced cough peak flow. Estimated mean cough peak flows for MI-E with manually assisted cough and MI-E alone were -4.006 L/s (95% CI -4.237 to -3.775) and -3.723 L/s (95% CI -3.953 to -3.492), respectively, surpassing the initial voluntary cough peak flow without MI-E assistance (-1.65 ± 0.53 L/s). The use of manually assisted cough and amount of TIV correlated with improved cough peak flow, emphasizing the importance of adequate in-expiratory support. No carry-over effect was associated with using manually assisted cough, highlighting the need to combine MI-E with manually assisted cough for each MI-E treatment to achieve optimal cough effectiveness.

Objective nasal airflow measures in relation to subjective nasal obstruction, trigeminal function, and olfaction in patients with chronic rhinosinusitis.

This study aimed to determine how nasal airflow measures and trigeminal function vary among patients with chronic rhinosinusitis (CRS) versus healthy controls and whether these measures are correlated with subjective nasal obstruction (SNO), olfactory function, and CRS control. Participants included CRS patients and healthy controls. After a structured medical history, nasal airflow (peak nasal inspiratory flow [PNIF]; active anterior rhinomanometry [AAR]), trigeminal function (trigeminal lateralization test, CO2 sensitivity), and olfactory "Sniffin's Sticks" odor identification test) tests were performed. SNO ratings were also obtained. Sixty-nine participants were included (37 men, 32 women, mean age 51 years). There was no significant difference for objective nasal airflow between patients and controls, but CRS patients had worse SNO, trigeminal function, and olfaction compared to controls. SNO, but not objective nasal airflow tests, was negatively correlated with CO2 sensitivity and odor identification. The perception of nasal obstruction does not only depend on nasal airflow, but may also be modulated by trigeminal function and other factors. Thus, the role of objective nasal airflow measures as a sole method of functional nasal obstruction assessment in CRS remains limited.

Pitot Tube Sensor Probe System for Simultaneous Airflow and Pressure Measurement of Expiration Inside Pulmonary Airway

Respiratory diseases, including the cronic obstructive pulmonary disease (COPD) are among the leading causes of death worldwide. To date, there is no physical examination procedure that can quantify important parameters within a specific lesion area inside the lung. In this study, we propose a novel sensor probe system consisting of a basket forceps and 2 pressure sensors to simultaneously measure the expiratory airflow and the static pressure inside the pulmonary airway. A Pitot tube mechanism using 2 pressure sensors is introduced in the system for measuring both the physical quantities. Small fiber‐optic pressure sensors with 0.3 mm diameter were utilized, and both the airflow rate and the static pressure characteristics were evaluated for obtaining the calibration curves. Finally, the proposed sensor system was implemented to measure both the airflow and pressure in an artificial ventilator and an experimental animal. The measurement of expired airflow and static pressure inside the airway of a rat with the diameter of 1.8 mm were demonstrated. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.