Measurements Of Flow Parameters Research Articles

Unveiling intricate foam behaviors and dynamic instabilities in a two-phase natural circulation loop with seawater

The use of seawater as an alternative emergency coolant in a nuclear power plant presents great potential to enhance the nuclear safety. The present study investigates the dynamic instabilities during the startup experiments of a natural circulation loop with seawater through synchronization of two-phase flow visualization and measurements of transient fluid flow parameters. The results reveal that in seawater the pressure drop oscillations (PDO) with nature of low-frequency pulse-type loop flow occurs at the modified heat flux of 531.56–654.80 kW/m2. On the other hand, the density wave oscillations (DWO) characterized by high-frequency oscillatory flow prevails at higher modified heat flux of 654.80–1844.46 kW/m2. For the loop with seawater, the flow patterns in the riser may evolve from dispersed bubbly flow, foam flow, foam and short slug flow due to the flashing effects, and foam and long slug flow periodically. The image analysis reveals that the foam fraction may decline from 75% to 52.2%, while the flow pattern transforms from the stage II (foam and cape bubbly flow) to III (foam and long slug flow). On the other hand, the flow pattern may evolve from bubbly flow, cap bubbly flow, turbulent slug flow, and long slug flow in de-ionized water. For DWO, the oscillatory frequency is found to be inlet temperature dependent. Interestingly, both fluids demonstrate identical frequencies of 0.06 Hz, 0.14 Hz, and 0.09 Hz, respectively, corresponding to the inlet temperature range of 40–52 °C, 52–65 °C, and 65–75 °C, despite significantly different evolution of two-phase flow patterns. Indeed, the density wave travels at the same speed through the loop operating at the same power for both seawater and de-ionized water, as the buoyancy force is the primary driving force for the present study. These findings contribute significantly to the better understanding of related industrial processes using seawater as the working fluid.

Quantitative evaluation of pulmonary hypertension using 4D flow MRI: A retrospective study

BackgroundPulmonary hypertension (PH) is a severe vascular disorder that may affect 50 % of patients with heart failure. Currently, right-sided heart catheterization is required to definitively diagnose PH. However, this method is invasive and thus may not be appropriate for repeated, long-term monitoring of PH patients. This retrospective study's aim was to evaluate whether 4D flow magnetic resonance imaging (MRI) can be used to quantitively measure flow parameters to identify patients with PH. MethodsThe study cohort included 97 patients recruited from a single institution and divided into three groups based on echocardiographic estimate of pulmonary artery systolic pressure (PASP): normal group with PASP<36 mmHg, borderline PH group with PASP of 37–50 mmHg, and PH group with PASP>50 mmHg. 4D flow MRI was used to quantitively assess blood flow and velocity, regurgitation, wall shear stress (WSS) and kinetic energy in the pulmonary artery trunk, right main pulmonary artery, and left pulmonary artery. Two experienced radiologists independently analyzed the MR images, blinded to clinical details. ResultsWe found a significant difference in WSS in the pulmonary artery trunk, right main pulmonary artery and left main pulmonary artery among the three patient groups. We also found significant differences in the kinetic energy and average through velocity in the pulmonary artery trunk and right main pulmonary artery, and significant differences in the flow rate in the right main pulmonary artery. ConclusionThese data suggest that 4D flow MRI can quantitate pulmonary artery flow parameters and distinguish between patients with and without PH.

An XCT study on three-dimensional characteristics of a spout-fluid bed

Spout-fluid beds are widely used in the chemical and petrochemical industries for excellent mixing and heat and mass transfer properties. Understanding the behavior of jets in spout-fluid beds is crucial for optimizing these processes. In this paper, we present a novel experimental method for studying the three-dimensional characteristics of jets in spout-fluid beds using X-ray computed tomography. By employing a gas–solid flow parameter measurement system, we propose an accurate experimental fitting method for voxel voidage values, enabling the three-dimensional reconstruction of the time-averaged voidage in the entire flow field of a spout-fluid bed. These data are then used to develop an image processing algorithm for identifying and quantifying gas jets in the flow field, allowing for measures of jet length, volume, and diameter. We further investigate the effects of static bed height, spouting gas velocity, and fluidizing gas flowrate on the three-dimensional characteristics of jets.

Non-circular pressure swirl nozzles injecting into stagnant air

As far as we are aware, all the previous studies have focused on circular injectors. Here, the effect of non-circular orifice shape on pressure swirl injector was investigated experimentally. For this purpose, three injectors; circular, square and rectangular were manufactured. The nozzles had the same cross-sectional area. Water was used as the working fluid and tests were conducted at room temperature and pressure. The Weber number varied from 484 to 1936. Flow parameters of the swirl jets were obtained by an in-house image processing code. The measured parameters were: discharge coefficient, spray angle, breakup length, lateral spread, SMD of drops and wavelength of surface waves formed on the cone. The influence of nozzle shape on all these parameters are discussed.A new breakup regime morphology for non-circular pressure swirl nozzles was defined. At lower Weber numbers, the air core was trapped inside the liquid sheet and relatively large ligaments were formed and separated from the edges (fiber breakup regime). As the Weber number was increased Rayleigh-Taylor instability produced cell-like structures near the nozzle exit. These cell-like structures eventually broke up at the thickened edges of the cells and formed Christmas tree like structures (Christmas tree regime). We found that all the measured flow parameters can best be correlated as a function of Reynolds number and Weber number based on liquid sheet thickness at nozzle exit. All these correlations were reported. Breakup length and lateral spread were heavily influenced by the breakup regime. In fiber breakup regime the breakup length and lateral spread increased with increasing Weber number. However, in Christmas tree (cellular) breakup regime, breakup length and lateral spread decreased with increasing Weber number.

Исследование способа измерения артериального давления ёмкостным интегрированным датчиком

A method of wireless measurement of blood flow parameters is investigated using an implantable passive capacitive sensor and an external reader. This device is designed to measure the parameters of blood flow in the human body, through the installation of a passive capacitive sensor and inductive coupling with an external reader device. The method of wireless measurement is based on the connection of resonant circuits at an operating frequency of 10 MHz. The mathematical calculation of the device circuit is presented. The result of the calculation was the dependence of the output voltage of the external reader on the change of capacitance in the implanted passive sensor. The values of the potential sensitivity of the device are obtained. The manufactured layout of the device and its parameters are presented. The mock-up allowed to investigate the dependences of the coupling factor of the circuits when using coils of an external reader of different sizes. Also the measurement of the output voltage of the external reader from the value of the passive sensor capacitance was made. The value of real sensitivity of the device layout was measured.

Flow Parameter Measurement of Intermittent Flow by PIV Interface Imaging Characteristics

Flow Parameter Measurement of Intermittent Flow by PIV Interface Imaging Characteristics

Doppler parameters in ductus venosus during the third trimester of pregnancy in goats.

The aim of the study was to assess hemodynamics in ductus venosus in the third trimester of pregnancy. Measurements of blood flow parameters in ductus venosus were performed using color Doppler combined with the pulsed-wave Doppler technique. In the analyzed period, the wave spectrum of blood flow in the ductus venosus had a specific pulsating character with two acceleration phases visible. The presented study showed an increase in peak systolic velocity, end-diastolic velocity, resistance index and pulsatility index in the last period of the third trimester of pregnancy. All Doppler parameters in the ductus venosus were correlated with the day of gestation. It has been shown that blood flow parameters and the Doppler spectrum depend on the gestational age. The obtained results may be useful for the future study of ductus venosus in fetal period in goats.

Measurement of Pneumatic Valve Flow Parameters on the Test Bench with Interchangeable Venturi Tubes and Their Practical Use.

A test bench with interchangeable venturi tubes was built to automatically measure the flow parameters of pneumatic valves of a wide range of sizes. This measuring stand contained components recommended by the ISO 6358 standard, an individually configured flow meter circuit, and HMI measurement and control panels. The flow meter circuit, individually configured with interchangeable venturi tubes, bypass loops, and Setaram thermal microflow meter, was calibrated using Molbloc/Molbox equipment. The tuning curve and theoretical flow rate characteristics of the tested valve were fitted to the flow rate measurement data. The best fit value of the critical pressure ratio was obtained using the numerical method of least squares minimization. The pneumatic valve with measured flow parameters was compared with data from the catalogue on the discharge characteristics of the compressed air tank. A practical solution for high-pressure tank discharge time using two valves connected in series to the hybrid tricycle bike (HTB) pneumatic propulsion system is presented. This article presents a solution to the practical problem of measuring the flow parameters of industrial pneumatic valves with a wide range of nominal diameters on a test bench with replaceable venturi tubes.

Feasibility and Clinical Value of Intraprocedural Doppler Ultrasonography Blood Flow Parameters During Peripheral Endovascular Procedures for Limb Salvage: A Pilot Study.

To investigate whether Doppler ultrasound (DUS) blood flow parameters could serve as quantifiable functional endpoints of peripheral endovascular arterial procedures for chronic limb-threatening ischemia (CLTI), influencing wound healing. This is a prospective single-center study investigating intraprocedural DUS parameters (pulsatility index [PI] and pedal acceleration time [PAT]) in quantifying immediate hemodynamic alterations in consecutive CLTI patients with wound, ischemia, and foot infection wound class ≥1 undergoing endovascular interventions. Primary endpoints were feasibility of preendovascular and postendovascular treatment measurements of PI/PAT, quantification of immediate PI/PAT modifications of the posterior and anterior foot circulation following revascularization, the correlation between PI and PAT, and 6-month complete wound healing. Secondary endpoints included the 6-month limb salvage (no major amputation) and complete and partial wound healing rates. A total of 28 patients (75.0% male) were enrolled, and 68 vessels were treated. The overall mean PAT values significantly decreased from 154.15±70.35 ms preprocedural to 107.21±49.6 ms postprocedural (p<0.01), and the mean PI values significantly increased from 0.93±0.99 to 1.92±1.96 (p<0.01). Postprocedural PAT at the anterior tibial (r2=0.804; p=0.346) and the posterior tibial arteries (r2=0.784; p=0.322) had a strong correlation and postprocedural PI at the anterior tibial (r2=0.704; p=0.301) and the posterior tibial arteries (r2=0.707; p=0.369) had a good correlation with 6-month complete wound healing. The 6-month complete and partial wound healing rates were 38.1% and 47.6%, respectively. Limb salvage was 96.4% and 92.4% at 6 and 12 months of follow-up, respectively. Pedal acceleration time and PI accurately detected immediate hemodynamic changes of foot perfusion following revascularization and could serve as prognostic factors of wound healing in patients with CLTI. Intraprocedural measurement of simple Doppler ultrasound blood flow parameters, Pulsatility Index (PI) and Pedal Acceleration Time (PAT), accurately detected immediate hemodynamic changes of foot perfusion following endovascular revascularization and could therefore serve as intraprocedural prognostic factors of wound healing in patients with chronic limb-threatening ischemia. This is the first time that PI has been proposed as a hemodynamic index of successful angioplasty outcome. The optimization of intraprocedural PAT and PI could be used to guide angioplasty and predict clinical success.

Multi – oil droplet recognition of oil-water two-phase flow based on integrated features

Multi-oil droplet target recognition is one of the applications of machine vision in the measurement of oil-water two-phase flow parameters, which could combine other algorithms to obtain the oil droplet velocity and the water holdup of oil water two-phase flow. Appropriate target representation features can improve the recognition effect of multiple oil droplets. However, due to shooting environment differences and quality differences of oil-water two-phase flow images, existing target representation features do not perform well in low-quality oil-water two-phase flow images. To improve the precision of multi-oil droplet target recognition in oil-water two-phase flow and reduce the miss rate, this paper constructs an integrated feature on the basis of aggregate channel features (ACF). The integrated feature named aggregate channel features with histogram of local gravitational feature（ACFHG） contains the color feature channels reflecting the overall color features of the oil droplet sample, the gradient amplitude channel reflecting the overall gradient of the oil droplet sample image, the gradient direction histogram feature channels reflecting the local gradient of the oil droplet sample image, and the local gravitational feature channels that ensure oil droplet target recognition in low quality photos and photos taken in complex shooting environments. Moreover, the rotation invariance is obtained by taking the oriented gradient histogram of the local gravitational feature to further improve the multi-oil droplet target recognition effect. Experiment results show that the average precision of multi-oil droplet target recognition using the integrated features is 83.38%, which is 9.93% higher than that with using ACF, and the miss rate is 9.13%, which is 57.18% lower than that with using ACF. Compared with other existing target detection methods, the method proposed in this paper still has an advantage in the rate of missed detection.

Multi-dimensional characteristics of upward bubbly flows in a vertical large-size square channel

Gas-liquid two-phase flows frequently occur in various flow channels in engineering systems with heat and mass transport processes. The channel geometry affects thermo-fluid behavior generally. Extensive research is done on gas-liquid two-phase flows in circular and annular channels with a wealth of local two-phase flow measurement data. Square channels are used in various engineering disciplines, but there has only been limited experimental research on two-phase flows in square channels with local flow parameter measurements. For two-phase flow analyses in square channels, knowledge of the flow characteristics and model validation against some key parameters, such as the drift-flux parameters and the interfacial area concentration, is crucial. An experiment for upward bubbly flows was conducted in a large square channel with an inside cross-section of 0.136 × 0.136 m. A four-sensor optical probe and a hot-film anemometer were used to measure local two-phase flow parameters at 66 points in an octant symmetric triangular cross-section at three axial locations. The measured two-phase flow parameters were the void fraction, axial gas velocity, axial liquid velocity, interfacial area concentration, and bubble Sauter mean diameter. The flow characteristics through flow development were investigated based on the local measurement data. The local measurement data directly determined the drift-flux parameters through their definitions. The distribution parameters determined through experimentation could be reproduced by the existing correlation for large circular pipes indicating that the flow characteristics in large square channels may be similar to those in large circular pipes. Based on existing drift-flux correlations for large circular pipes, the void fractions in the current experiment could be fairly predicted. Furthermore, the interfacial area concentrations could be predicted by existing correlations with reasonable accuracy.

Quantitative Measurements of Macular and Optic Nerve Head Blood Flow Parameters Following Cataract Surgery in Eye Department, Red Cross Tertiary General Hospital, Athens, Greece

Objective: To evaluate the effect of uncomplicated cataract surgery on macular and optic nerve head blood flow with Optical Coherence Tomography Angiography (OCT-A). Retinal vascular changes and macular vessel remodeling following cataract surgery is an area of interest, as the effect, cause and duration of such changes remain debatable.&#x0D; Setting: Eye Department, Red Cross Tertiary General Hospital, Athens, Greece.&#x0D; Methods: In this study, we recruited cataract surgery candidates who had regular post operative visits and underwent longitudinal OCT-A examinations before and after surgery.&#x0D; Results: Macular vessel density increased in the post operative visits both in the superficial (SCP) and deep capillary network (DCP) (P&lt;0.001) and showed a persistent effect over 3 months follow-up. Macular thickness increased over the first postoperative month, but returned to preoperative values at 3 months. Foveal avascular zone (FAZ) measurements and vessel density at radial peripapillary capillaries (RPC) were unaffected.&#x0D; Conclusions: OCT-A enables a quantitative analysis of blood flow by regular patient monitoring. In this study, we found that after cataract surgery, macular blood flow increased significantly. The reason for this could be attributed to post operative inflammatory process or vascular remodeling due to change in retinal metabolic demands.

Comprehensive assessment of the dynamics of angiogenesis in patients with psoriasis treated with methotrexate

Background. Evaluation of the severity of pathological angiogenesis in patients with psoriasis can be considered as a promising direction for monitoring the activity of the disease and the effectiveness of systemic therapy.&#x0D; Aims. Evaluation of interconnections between indicators of angiogenesis in the skin and nail bed of psoriasis patients with clinical characteristics of disease course and therapeutic response to the use of methotrexate by a comprehensive study of the morphometric data dynamics of videodermatoscopy in vascular bed of the skin, the severity of blood flow in the dermis and nail bed during ultrasonic power dopplerography and plasma concentrations of vascular endothelial growth factor (VEGF) and endothelin-1 (En-1).&#x0D; Materials and methods. Work is based on the data analysis from a survey of 82 patients with moderate to severe psoriasis vulgaris in the acute stage, who were first prescribed methotrexate in the form of subcutaneous injections at a dose of 1015 mg per week in combination with folic acid 5 mg per week. Before treatment and three months after the start of methotrexate therapy, all patients underwent videodermatoscopy with dimension of the density and size of dilated skin capillaries, ultrasonography of psoriatic plaques and nail bed of affected nails and measurement of doppler blood flow parameters and concentration of VEGF and En-1 in blood plasma.&#x0D; Results. A direct correlation was established between the average diameter of dilated skin capillaries (vascular glomeruli), the degree of increased blood flow in the doppler energy study of psoriatic plaques skin area and the plasma concentration of VEGF and En-1 and values of PASI, BSA, sPGA and DLQI indices, as well as the severity of doppler blood flow of the nail bed and NAPSI index (r = 0.210.73). Under the influence of methotrexate treatment, a decrease in diameter and density of vascular glomeruli (16.2 [12.9; 22.5] versus 25.2 [17.1; 33.7] m before treatment (p = 0.002) and (44.6 [31.6; 53.3] versus 53.5 [34.6; 67.4] before treatment (p = 0.04), respectively), the degree of blood flow in area of psoriatic plaques and the concentration of VEGF and En-1 (12.5 [6.7; 26.8] pg/ml versus 19.5 [4.7; 48.1] pg/ml after treatment (p = 0.002) and En-1 (168.2 [97; 319] versus 274.5 [146; 439] pg/ml(p = 0.003), respectively) was observed.&#x0D; Conclusions. Studied indicators of angiogenesis can be used as additional criteria for assessing the degree of activity and achieving clinical improvement/remission during systemic therapy in patients with moderate and severe psoriasis.

Mass flow rate measurement of gas-liquid two-phase flow using acoustic-optical-Venturi mutisensors

The measurement of multiphase flow parameters is essential for the online monitoring of industrial production and energy metering. In this paper, a multi-sensor experimental measurement device is designed based on NIR, acoustic emission sensors, and throated Venturi. The measurement information is decomposed using modal decomposition, and the characteristic variables of the gas volume fraction are extracted by flow noise decoupling and light attenuation analysis. A new gas volume fraction model is proposed based on Gradient Boosting Decision Tree (GBDT) through feature-level fusion, and the Mean Absolute Percentage Error (MAPE) of the gas volume fraction prediction models is within 4% for the three flow patterns. A new flow rate model is established based on the Homogeneous and Collins models. Laboratory results indicate that the MAPE of the flow rate model is 1.56%, and 98.61% relative deviations are within ±20% error band. The study provides a new method for online measurement of multiphase fluid motion and a theoretical basis for sensing mechanism and measurement of multiphase flow.

МАКСИМАЛЬНОЕ РАБОЧЕЕ УСТЬЕВОЕ ДАВЛЕНИЕ КАК ПОКАЗАТЕЛЬ ПРОИЗВОДИТЕЛЬНОСТИ ПАРЛИФТНОЙ СКВАЖИНЫ

The possibility of estimating the productivity of a geothermal well operating in the steam-lift mode without measuring flow parameters is considered. An evaluation technique based on mathematical modeling of the flow in the wellbore is proposed. The methodology involves the use of parameters required for determination at the end of well construction and the value of the maximum working wellhead pressure, which can be determined during the initial production process, for the calculation.

A Field High Resolution Measurement Method for Irregular Surface Electrostatic Potential

Characterized by noninvasiveness and high sensitivity, the noncontact electrostatic testing technology has been widely used in scientific research and engineering practices such as electrostatic charge imaging, high-voltage insulator analysis, biological sensing, and gas—solid two-phase flow parameter measurement. However, in many practical applications, scanning electric potential microscope (SEPM) technologies focusing on high spatial resolution cannot meet the testing requirements of charged objects with irregular 3-D structures and flexible activities. Based on the principle of direct inductive electrostatic potential measurement and a six-axis robot arm, a 3-D scanning method for noncontact electrostatic potential measurement is proposed in this article. A low-noise electrostatic potential sensor with both high sensitivity and high accuracy was designed via positive feedback circuit technology. A calibration system was built, which has an adjustable excitation signal, progressive spatial accuracy, and variable 3-D attitude. The experimental data verify the effectiveness of this method. The correlation between the signal characteristics and the physical size of the calibration device was statistically analyzed. The effects of parameters such as the amplitude and frequency of the excitation signal, speed, and normal distance of the robot arm scanning on the resolution of the test results were investigated. The testing results show that the 3-D spatial resolution of dc and low-frequency ac potential distribution reached 200 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> .

Soft measurement of oil–water two-phase flow using a multi-task sequence-based CapsNet

Flow parameters measurement facilitates the understanding of two-phase flow. Due to the changeable structures of the flow, the prediction of superficial velocity of oil–water two-phase flow in large diameter pipes is still a challenging problem. Therefore, we first conducted a vertical upward oil–water two-phase flow experiment in a 125 mm ID pipe, and obtained the response signals under different flow conditions by a vertical multi-electrode array (VMEA) conductance sensor. Then, new data pre-processing (1D to 2D) techniques and information fusion techniques (network channels) are employed. Moreover, the front-end structure of the network is optimized using a combination of attention block and residual structure, and the middle structure is optimized using inception block; on the other hand, the back-end structure of the original capsule network is innovatively changed so that it can handle both the flow pattern classification and superficial velocity prediction tasks. The dynamic routing algorithm has also been improved to speed up model training. Extensive experiments validate the effectiveness of the improved modules. Finally, we compare the proposed network with its variants and other competing networks. The better performance results show that our multi-task sequence-based CapsNet has great potential for dealing with high-dimensional, time-varying and nonlinear problems in multiphase flow.

Application of ultrasound technique to evaluate the testicular function and its correlation to the sperm quality after different collection frequency in rams.

The frequency of semen collection is a crucial factor to consider in the rams performance inside breeding centers workout. To evaluate this factor, ram Breeding Soundness Evaluation could include sperm quality evaluation and new predictive and non-invasive tools such as ultrasound technique. In this work, an advanced ultrasonography technology, analyzing the testicular volume, echotexture, and vascular function, was used in three different frequencies of semen collection (abstinence frequency, AF; standard frequency, SF; and intensive frequency, IF). Semen samples were cooled (15°C, 6 h) and evaluated in terms of production, motility, viability, apoptosis, and content of reactive oxygen species. Correlation coefficients were calculated between ultrasonography measurements of echotexture and blood flow and sperm quality parameters. Our results showed an increase in the testicular echotexture when the frequency of semen collection was intensified. Doppler parameters (PSV, RI, PI, TABF) increased (P ≤ 0.05) when the frequency of semen collection was intensified. The sperm motility and functionality decreased in the samples of IF (P ≤ 0.05), evidencing the frequency of semen collection's influence. Moreover, moderate positive correlations were established among echotexture and different Doppler parameters with motility parameters in SF. Furthermore, the influence of abstinence days on AI success was analyzed in a field assay. The highest fertility rates were obtained when males had two to five abstinence days. To conclude, frequency of semen collection could be influenced in terms of semen quantity and sperm quality, showing changes in parenchyma echotexture and testicular vascularization. The standard semen collection frequency was the most adequate option. In addition, ultrasonography may be a predictive tool for estimating variations in the sperm quality of donor rams subjected to different frequencies of semen collection in reproduction centers.

Physics-informed multi-fidelity learning-driven imaging method for electrical capacitance tomography

The electrical capacitance tomography is considered to be a promising non-invasive visualization method for the measurement of multiphase flow parameters, but low-quality tomograms limit the reliability and accuracy of measurements. In order to overcome this limitation and bottleneck, the physics-informed data-dependent prior learned from the given samples is introduced and coupled with the measurement mechanism and the domain knowledge modeled by a new L1/L2 norm-based regularizer into a new optimization imaging model in this study. To improve the convergence and reduce the computational load, the built imaging model is solved by a new numerical scheme driven by the split Bregman method and the forward–backward splitting method. A new physics-informed robust sparse extreme learning machine method that not only obeys the measurement mechanism in training but also promotes the robustness and performance of the model is proposed and used to build a novel multi-fidelity learning method to infer the physics-informed data-dependent prior. The new imaging method achieves multi-source data fusion, leads to new changes in reconstruction algorithms, increases the complementarity and diversity of image priors, unifies the image reconstruction and multi-fidelity learning method, and improves robustness, numerical stability and flexibility of the model. The reconstruction results show that the new imaging method achieves more accurate reconstruction with reduced sensitivity to noise compared to important and popular imaging methods. This study leads to new changes in imaging algorithms and mining and use of image priors, and serves as a catalyst for the paradigm shift in image reconstruction.

Supersonic combustion diagnostics with dual comb spectroscopy

Supersonic engine development requires accurate and detailed measurements of fluidic and thermodynamic parameters to optimize engine designs and benchmark computational fluid dynamic (CFD) simulations. Here, we demonstrate that dual frequency comb spectroscopy (DCS) with mode-locked frequency combs can provide simultaneous absolute measurements of several flow parameters with low uncertainty across a range of conditions owing to the broadband and ultrastable optical frequency output of the lasers. We perform DCS measurements across a 6800–7200 cm−1 bandwidth covering hundreds of H2O absorption features resolved with a spectral point spacing of 0.0067 cm−1 and point spacing precision of 1.68 × 10−10 cm−1. We demonstrate 2D profiles of velocity, temperature, pressure, water mole fraction, and air mass flux in a ground-test dual-mode ramjet at Wright-Patterson Air Force Base. The narrow angles of the measurement beams offer sufficient spatial resolution to resolve properties across an oblique shock train in the isolator and the thermal throat of the combustor. We determine that the total measurement uncertainties for the various parameters range from 1% for temperature to 9% for water vapor mole fraction, with the absorption database/model that is used to interpret the data typically contributing the most uncertainty (leaving the door open for even lower uncertainty in the future). CFD at the various measurement locations show good agreement, largely falling within the DCS measurement uncertainty for most profiles and parameters.