Ali Bahadır Olcay

Numerical investigation of coalescing plate system to understand the separation of water and oil in water treatment plant of petroleum industry

ABSTRACT The most widely utilized process of produced water treatment is considered to be use of coalescing or corrugated plate systems in the oil industry because these systems have promising results in the acceleration of the separation process. Even use of corrugated plate systems seem to be effective in separation processes, the geometrical parameters of the plate system could greatly influence the performance of separation process. In this study, a two-dimensional computational fluid dynamics model for coalescing plates was developed to investigate Reynolds number and plate hole shape on separation efficiency. Spacing between plates was set to 12 mm while fluid mixture’s Reynolds number varied between 5 and 45 for the computational model. Hole profile and dimensions were determined to be cylindrical, rectangular and ellipse shapes as 10, 15 and 20 mm based on hydraulic diameter definition, respectively. Furthermore, when hole profiles of coalescing plates were chosen to be ellipse and rectangular shapes, separation efficiency nearly stayed constant regardless of hole dimension. The study also reported that change of oil fraction from 5% to 15% caused approximately 30% increase in the separation efficiency. The investigation also revealed Reynolds number of the mixture was inversely proportional to the separation efficiency. It was also found that the highest separation efficiency was obtained for a cylindrical shape with a hole diameter of 15 mm when distance between plates was 12 mm and Reynolds number was 18.

Assessment of the work efficiency with exergy method in ageing muscles and healthy and enlarged hearts

Thermodynamic aspects of skeletal and cardiac muscle work performance are assessed with the data obtained from the literature. Since the second law muscle work efficiency decreases with declining metabolic energy conversion efficiency in the mitochondria, followed by structural failure of the muscles during ageing, the thermodynamic aspects of the muscle work ageing process were simulated by incorporating the decreasing second law muscle work efficiency with the exercise data obtained with the healthy young adults. Within limits of the data analysed here, glucose utilisation ability of the cardiac muscle appears to be the most critical factor determining its work performance. The left and the right ventricles of the enlarged heart had the ability of utilising approximately 3.5 and 2.7 times less glucose, respectively, than their healthy counterparts. The work performance and the entropy generation by the enlarged and the healthy hearts maintained the same ratios.

3D Computational Analysis of Thermal and Hydraulic Performance of Louvered Fin Heat Exchanger With Variable Louver Angle and Louver Pitch

In the present study, 3-D numerical simulations on heat and fluid flow characteristics of double-row multi-louvered fins heat exchanger are carried out. The heat transfer improvement and the corresponding pressure drop amounts were investigated depending on louver angles in the range of 20° ≤θ≤ 30°, louver pitches of Lp = 2,7mm, 3,5mm and 3,8mm and frontal velocities of Uin between 1.22 m/s and 3 m/s. The results are reported in terms of Colburn j-factor, Fanning friction factor f and area goodness factor j/f based on louver angle, louver pitch and Reynolds number. To understand local behavior of flow around louvered fins and heat exchanger tubes, flow visualization results of velocity vectors and stream-lines with temperature counters are presented. It is investigated that increasing louver angle enhances convective heat transfer while hydraulic performance decreases due to increased pressure drop. The flow noticeably behaves louver directed for all louver angles The flow can easily travel between different fins. This case study has been done to design and manufacture an industrial louver fin heat exchanger.Copyright