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Predictions of pressure drops in helical pipes using the Relap5/mod3.3 code are explored, despite the code’s limitations in modeling such geometries. To address this, the code was modified to incorporate helical tube geometries and correlations for frictional pressure drops under both single-phase and two-phase flow conditions. Comparisons with experimental data on pressure drops across test sections with varying curvature ratios, operational pressures, and mass flow rates were made. The study demonstrates that the modified Relap5 code significantly improves the accuracy of frictional pressure drop predictions for the examined experimental data.

Guidewire-based pressure measurement is essential for diagnosing coronary artery disease. However, the impact of the guidewire on local hemodynamics and diagnostic outcomes is not fully understood. In this study, we propose a generalized reduced-order model (ROM) to accurately predict the trans-stenotic pressure drop in arteries. A key advantage of this model is that the viscous term does not rely on empirical parameters, making it applicable to both scenarios with and without guidewire insertion, and across varying stenosis severities. The proposed model demonstrates good accuracy compared to 3D idealized numerical models, achieving an average prediction error of 3.61% for cases without a guidewire and 4.53% for cases with a guidewire. Furthermore, when applied to a patient-specific model, it achieves comparable or better results than previously published ROMs. Finally, this ROM is employed to investigate the shifting relative importance of different components of the trans-stenotic pressure drop at various stenosis severities, and to provide further insights into the guidewire’s influence on FFR measurements.

The morphological vulnerability of atherosclerotic plaques, such as fluttering motion under pulsatile flow, poses diagnostic challenges in conventional fractional flow reserve (FFR) assessment. In this study, we investigate the hemodynamic impact of a fluttering plaque using a physical model of mild (40%) stenosis with and without an elastic plaque under stenotic flow. High-speed particle image velocimetry (PIV) and differential pressure measurements were employed to characterize flow patterns and pressure drop waveforms. While both models produced comparable time-averaged pressure drops, the Fluttering Plaque model exhibited extended recirculation zones, and elevated root-mean-square (RMS) fluctuations in pressure drop waveforms. The effects of the fluttering plaque on the distribution of turbulent kinetic energy (TKE) provides insight into the observed results. Our findings suggest that waveform-derived metrics, particularly the RMS amplitude of pressure drop fluctuations, may serve as novel hemodynamic indicators for detecting vulnerable plaques that remain undetected by time-averaged indices such as FFR.

Predicting pressure drop in multiphase flow is crucial for optimizing tubing size, wellhead pressure (WHP), completion design, cost management, and other production-phase objectives. While various correlations and models exist to calculate pressure drops, their accuracy diminishes significantly when applied to outlier datasets beyond their intended parameter ranges. Not only that, as reported by many studies, most of the empirical correlations and mechanistic models have an error, which is quite high and intolerable. This study introduces a novel Adaptive Neuro-Fuzzy Inference System (ANFIS) model for accurately predicting pressure drops in vertical wells carrying multiphase fluids. A comprehensive dataset of 335 experimental records was compiled from diverse sources to encompass a wide range of parameters, ensuring the robustness of the proposed model. Key input parameters include WHP, oil rate, water rate, gas rate, inner diameter, surface temperature, and flow length. The ANFIS model was rigorously evaluated using different methods, such as cross plot, error distribution, Kruskal-Wallis (KW) test, error boxplot and violin graphs, Confidence Interval (CI), and statistical error metrics. The latter includes Average Absolute Percentage Error (AAPE), Root Mean Square Error (RMSE), and the coefficient of determination (R²) to prove the ANFIS model’s performance. The proposed ANFIS model was compared with the most commonly used published models. Results demonstrate that the ANFIS model outperforms existing methods, achieving an AAPE of 2.92%, an RMSE of 1.9638%, and an R² of 0.9645. KW test, error boxplot, violin graphs, and CI results indicated that the best model for predicting pressure drops is the proposed ANFIS model. These findings establish the ANFIS model as a reliable and superior tool for predicting pressure drops in vertical wells with multiphase flow, offering significant advancements in design accuracy and operational efficiency.

Accurately calculating the bottom hole flow pressure of a multi-layer stacked sandstone reservoir (hereinafter referred to as a multi-layer reservoir) is the basis for production splitting, oil well dynamic analysis, and reasonable work system determination in the development of multi-layer reservoirs. The bottomhole flow pressure model for single-layer oil reservoirs does not consider interlayer interference and the pressure drop caused by fluid flow in the wellbore, which doesn’t comply with the characteristics of multi-layer combined production, and the use of the maximum bottomhole flow pressure of the oil layer as the bottomhole flow pressure of each oil layer to adjust the production system of each oil layer doesn’t meet the requirements of other oil layer regulation. Firstly, starting from fluid mechanics, the frictional effect generated by fluid flow in the wellbore is systematically considered, and the relationship between wellbore frictional pressure drop and flow distance is established. The pressure drop formula generated by fluid flow in the wellbore is derived; Secondly, from the perspective of seepage mechanics, a formula for the bottom hole flow pressure of a single-layer reservoir was obtained. Combined with the expression for the difference in bottom hole flow pressure of each oil layer in the development of a multi-layer reservoir and the pressure drop expression for fluid flow in the wellbore, a bottom hole flow pressure model for each oil layer in the development of a multi-layer reservoir was established (hereinafter referred to as the multi-layer reservoir bottom hole flow pressure model). Substitute various parameters into the bottomhole flow pressure model of multi-layer oil reservoirs, and the error between the calculated values and the actual test values in the field is 0.10%~1.30%, with an average error of 0.82%, meeting the actual needs of the site. There is a significant difference in the bottom hole flow pressure values of each oil layer in the co production reservoir. The multi layer reservoir bottom hole flow pressure model can accurately calculate the bottom hole flow pressure of each oil layer, avoiding the inability to accurately adjust the production system of multiple oil layers for the same bottom hole flow pressure. It can provide technical support for the development of a reasonable drainage system for on-site co production oil wells and the realization of high and stable production.

The modernization of compressed air systems represents both a strategic challenge and an opportunity to achieve a balanced symmetry, understood as the equilibrium among energy efficiency, industrial optimization, and operational sustainability. This study combines the experimental validation of a centralized compressed air system operating under real industrial conditions with a bibliometric analysis that contextualizes the work within global research trends in energy efficiency and industrial optimization. The system, implemented at the Oleohidráulica Company in Cienfuegos, Cuba, consists of two BOGE C 22-2 screw compressors and a newly upgraded distribution network. The analysis involved calculating pressure drops using the methodology proposed by Atlas Copco and verifying the results in situ through measurements at the most distant point of the network. The obtained pressure drop of 0.059 bar, below the international threshold of 0.1 bar, confirms the adequacy and reliability of the design. Moreover, the discussion highlights future perspectives for improvement, where integrating a hybrid approach that combines computational fluid dynamics (CFD) simulations with experimental validation could enhance the accuracy of flow and pressure predictions and facilitate the optimization of the pipeline network design. Overall, the study demonstrates that while the current system complies with international standards, achieving symmetry as an operational balance among efficiency, reliability, and sustainability remains an ongoing process, guiding future optimization efforts.

Reducing particulate emission is a key factor in improving the air quality as particulate matter cause respiratory diseases. In this study, an axial cyclone was selected from several existing technologies to reduce particulate emissions owing to its outstanding separation performance and low-pressure drop. To enhance the axial cyclone, the fastest descending curve among the lines that pass through two points was selected; it induces faster momentum changes from the axial to the tangential direction. Therefore, the selected cycloid curve was applied to the vanes and body of the axial cyclone. The particle trajectory was simulated using a discrete phase model (DPM) in ANSYS Fluent ver. 2020 R2. Furthermore, the external structure of the axial cyclone was optimized via multi-objective optimization based on response surface methodology. Additionally, experiments were conducted to evaluate the proposed cyclone performance. Without applying the cycloid curve, the separation efficiency and the pressure drop were 73.6% and 1013.3 Pa, respectively. In the case of the cycloid-applied axial cyclone, however, the separation efficiency and pressure drop were 91.6% and 1109.6 Pa, respectively. Thus, the application of the cycloid curve improved the cyclone performance by approximately 24.5%.

An investigation of steady laminar flow in transversely corrugated conduits is presented, with the velocity distribution and frictional resistance being characterized for the fully developed region, while the incremental pressure drop, and hydrodynamic entrance length are examined for the developing region. The velocity field throughout both flow regimes is modeled using an innovative analytical approach based on epitrochoidal coordinate transformations. It is demonstrated that in fully developed flow, the Fanning friction factor is reduced with either an increase in corrugation count at fixed amplitude or with larger corrugation amplitude at fixed wave number. Conversely, in the developing flow region, both the incremental pressure drop, and entrance length are found to increase with greater corrugation amplitude or number of boundary waves. These findings are shown to provide valuable insights for the optimization of corrugated conduit designs in applications where entrance effects are significant, such as in compact heat exchangers and microfluidic systems.

The depletion of fossil fuels and climate change are major worldwide problems. Unlike hydrocarbon resources, solar energy is a clean, inexhaustible, and sustainable power source to meet all of humankind’s energy demands. Solar chimney power plants (SCPPs) having a simple design are capable of generating large‐scale solar powered electricity. The systems have three primary components: a chimney, turbine, and collector. The optimization of the chimney geometry plays a key role in achieving the peak efficiency of SCPPs. In the current work, a three‐dimensional (3D) model on the basis of the Manzanares prototype with a chimney height ( H ) of 194.6 m and radius ( R ) of 5.08 m is developed to identify optimal height for the innovative constricted chimney section configurations via ANSYS FLUENT. The height of the narrowed chimney sections varies as 1/4, 1/8, 1/16, and 1/32 of H for a fixed radius as 1/3 of R . The findings indicate that the power output ( P o ) increases with decreasing the narrowed section height from H /4 to H /32 owing to enhanced mass flow rate and turbine pressure drop. The highest P o of 65.9 kW is gained with the configuration with the height of H /32 and P o enhances by 43.3% compared to the base case at 1000 W/m 2 . The novel equations are improved from the numerical data to estimate the performance features. Besides, the impact of the narrowed section radius on the performance is examined to optimize the dimensions of the constricted section. It is found that a decrease in the narrowed section radius from R /3 to R /5 for a constant height of H /32 leads to a reduction in P o by 1.2% because of a remarkable decrease in mass flow rate. H /32 and R /3 can be optimum height and radius value for the reduced chimney section to augment system efficiency.

This study investigates in-station pressure drop mechanisms in a shale gas gathering system, providing a quantitative basis for flow system optimization. Computational fluid dynamics (CFD) simulations, based on field-measured parameters related to a representative case (a shale gas platform located in Sichuan, China) are conducted to analyze the flow characteristics of specific fittings and manifolds, and to quantify fitting resistance coefficients and manifold inlet interference. The resulting coefficients are integrated into a full-station gathering network model in PipeSim, which, combined with production data, enables evaluation of pressure losses and identification of equivalent pipeline blockages. The results indicate that the resistance coefficients, valid only for fittings under the studied field-specific geometries, are 0.21 for 90° elbows in the fully open position, 0.16 for gate valve passages in the fully open position, and 2.3 for globe valve passages. Manifold interference decreases with lower high-pressure inlet values, whereas inlets farther from the high-pressure side experience stronger disturbances. Interestingly, significant discrepancies between simulated and measured pressure drops reveal partial blockages, corresponding to effective diameter reductions of 65 mm, 38 mm, 44 mm, 38 mm, and 28 mm for Wells 1#, 3#, 5#, and 6#, respectively.