Computational Fluid Dynamic Modeling to Determine the Resistance Coefficient of a Saturated Steam Flow in 90 Degree Elbows for High Reynolds Number

Abstract

The pressure drop in 90 deg elbows under the operating conditions of geothermal power plants in Mexico is studied using the computational fluid dynamics model. The elbow resistance coefficient was calculated for a steam flow with high Reynolds numbers (1.66–5.81 × 106) and different curvature ratios (1, 1.5, and 2). The simulations were carried out with the commercial software ANSYScfx, which considered the Reynolds-averaged Navier–Stokes (RANS) compressible equations and the renormalization group (RNG) k–ε turbulence model. First, the methodology was validated by comparing the numerical results (velocity and pressure) with published data of airflow (25 °C, 0.1 MPa) with high Reynolds numbers. Then, scenarios with different diameters (0.3–1.0 m) and conditions of the working fluid (0.8–1.2 MPa) were simulated to obtain velocity, pressure, density, and temperature profiles along the pipeline. The temperature and density gradients combined with the compressible effects achieved in the 90 deg elbows modified the flow separation, pressure drop, and resistance coefficient. Based on the resistance coefficient, factors were generated for a new equation, which was integrated into Geosteam.Net to calculate the pressure drop in a pipeline at the Los Azufres geothermal power plant. The difference with the data measured by a pressure transducer was 7.59%, while the equations developed for water or air showed differences between 11.23% and 45.22%.

Computational fluid dynamic analysis for investigating the influence of pipe curvature on erosion rate prediction during crude oil production

“…This phenomenon can be explained based on the theory that when fluid moves through a curved path, it attaches itself to the curved surface preferentially and causes the fluid to flow faster than expected. This hypothesis confirms the Coanda principle (López-López et al, 2019). This phenomenon was more pronounced for model design-4, which can be seen in Fig.…”

“…Dynamic pressure deals with pressure exerted by the fluid in maximum displacement, while static from its name is concerned with the pressure exerted by the fluid around the re-circulation zone. These two (2) pressures are experienced during fluid flow through a pipe (López-López et al, 2019).…”

A Numerical Investigation of the Influence of Geometric Parameters on the Performance of a Multi-Channel Confluent Water Supply

“…Manually regulating the frequency converter (3) leads to the variation of centrifugal pump speed, which in turn affects the change of flow rate in the channel. An air-vent valve (13) was installed between the air compressor (14) and the pneumatic valve (9), which can adjust the opening and closing time of the pneumatic valve. The switching sequence of the pneumatic valve is controlled by a data acquisition (DAQ) card (15).…”

“…Previous studies feature two main research methods: computational fluid dynamic (CFD) analysis and experimental measurements. In [14], the pressure losses of a 90 degree elbow were investigated by the two analyses, and the results show good agreement, and in [15], the pressure Furthermore, the MCCS structure in the field of fire protection can be described as several parallel channels that combine at a manifold and then flow out. In order to obtain the minimum energy loss, it is necessary to analyze the sensitivity of the geometric parameters of the MCCS structure to pressure loss and pressure drop.…”

“…Previous studies feature two main research methods: computational fluid dynamic (CFD) analysis and experimental measurements. In [14], the pressure losses of a 90 degree elbow were investigated by the two analyses, and the results show good agreement, and in [15], the pressure losses in 90 degree elbow considering the geometry were studied both with numerical analysis and experimental. In [7], the authors studied the pressure losses of the turbulent flow field for a sharp 90 degree elbow and a plugged tee junction by experiment and simulation.…”