A Mechanistic Slug-Liquid-Holdup Model for Different Oil Viscosities and Pipe-Inclination Angles

The flow patterns in two phase and multi-phase flows is a significant factor which influences many other parameters such as drag force, drag coefficient and pressure drop in pipe lines. One of the major streams in the gas and oil industries is oil-water two phase flow. The main flow patterns in oil-water flows are bubbly, slug, dual continuous, stratified and annular. In the present work flow patterns in two phase oil-water flow were investigated in a 0.5in diameter pipe with length of 2m. 3D simulation was used for this pipe and six types of mesh grid were used to investigate mesh independency of the simulation. The proposed numerical analyses were performed by a CFD package which is based both on volume of fluid (VOF) and Eulerian-Eulerian methods. The results showed that some flow patterns can be simulated better with VOF method and some other maybe in Eulerian-Eulerian method, so these two methods were compared with together for all flow patterns. The flow patterns may be a function of many parameters in flow. One of the important parameter which may affect flow patterns in pipe line is pipe inclination angle; therefore flow patterns in the different pipe inclination angles were investigated in two phase oil-water flow. The range of inclinations has been varied between −45 to +45 degree about the horizon. In the presented simulation oil is mixed with water via a circular hole at center of the pipe, the ratio of oil surface to water surface at entrance is 2/3 so water phase was considered as the main phase. Flow patterns were investigated for every angle of pipe and numerical results were compared with available experimental data for verification. Also the flow patterns simulated by numerical approaches were compared with available flow regime maps in the previous literatures. Finally, effect of pipe inclination angle and flow patterns on the pressure loss were investigated comprehensively.

Download Full-text

A Unified Model for Slug Flow in Upward Inclined Pipes

Journal of Energy Resources Technology ◽

10.1115/1.2835324 ◽

1995 ◽

Vol 117 (1) ◽

pp. 7-12 ◽

Cited By ~ 24

Author(s):

H. Felizola ◽

O. Shoham

Keyword(s):

Experimental Data ◽

Slug Flow ◽

Entire Range ◽

Flow Behavior ◽

Flow Characteristics ◽

Unified Model ◽

Liquid Holdup ◽

Two Phase ◽

Inclination Angles ◽

Inclined Pipes

The effect of pipe inclination on upward two-phase slug flow characteristics has been studied both experimentally and theoretically. Experimental data were acquired for the entire range of inclination angles, from horizontal to vertical. New correlations were developed for slug length and liquid holdup in the slug body as a function of inclination angle. A unified model has been developed for the prediction of slug flow behavior in upward inclined pipes. Reasonable agreement is observed between the pressure drop predicted by the model and the experimental data.

Download Full-text

Sun Load Analysis and Testing on Automotive Front Lighting Products

Light & Engineering ◽

10.33383/2019-026 ◽

2020 ◽

pp. 116-122

Author(s):

Emre Öztürk ◽

Mehmet Aktaş ◽

Tunç Şenyüz

Keyword(s):

Prolonged Exposure ◽

Hot Spot ◽

Load Test ◽

Angle Of Incidence ◽

The Sun ◽

Solar Simulator ◽

Automotive Lighting ◽

Inclination Angles ◽

Plastic Parts ◽

Load Simulation

The purpose of this research is to reach good correlation between sun load simulation and solar focusing test for exterior automotive lighting products. Light coming from sun is highly collimated (parallel rays) and focusable from lenses with concave structure. Focusing incidence leads to a hot spot on lens surrounding plastic parts which may cause melting failures at high temperature zones. Sun load simulation is performing to eliminate risk of discoloration, deformation, out gassing, coating failures and fire with prolonged exposure from field. Irradiance values in W/m2 defined in simulation as heat source depending of an angle of incidence of the sun radiation. At first step, simulation is performing with 5 degree intervals to define the critical zones then intervals decreased to 2 degree to detect the critical azimuth and inclination angles. Critical azimuth and inclination angles is checking with ray trace analysis to check the bouncing of sun rays and possible solution to eliminate focuses with design solutions. After numerical analysis to release and validate the automotive lighting products regarding the sun load test, measurement with first parts is necessary. Measurement is performing for all critical angles which have been detected at simulation with thermal camera under ultra high-collimation solar simulator. Measured temperatures are settled according to environment conditions and correlation is checking with simulations.

Download Full-text