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EgeUn###, The objective of this study was to predict total friction losses in drip irrigation laterals with cylindrical integrated in-line emitters at different spacing using Computational Fluid Dynamics (CFD) simulation method. Two types of drip irrigation laterals with different technical specifications were used in the study. In the laboratory, the total friction losses were measured in the laterals for different velocities. In CFD analysis, standard k-epsilon, RNG k-epsilon, realizable k-epsilon, Reynolds Stress (RSM) with Linear Pressure-Strain (LPS) turbulence models and standard wall function, non-equilibrium wall function, enhanced wall treatment were considered. CFD simulation results were compared with experimental total friction losses in laterals. The highest prediction was obtained by RSM turbulence model with LPS using standard wall function with the lowest values of MAPF (2.96%) and RMSE (369 Pa).

The objective of this study was to determine the hydraulic properties of a flat type emitter using Computational Fluid Dynamics with different turbulence models and model options. in addition, it is aimed to investigate the effects of the emitter hydraulic properties on the design when the same emitter is used in drip irrigation pipes with different wall thicknesses. the lowest mean percentage deviation between the measured flow rates and the calculated flow rates with turbulence models was found as 0.70% and 0.74% in the SST k-omega and Stress-Omega RSM turbulence model for the wall thickness of 0.25 mm pipe, respectively. Also, the mean percentage deviation for the laminar turbulence model was found to be -1.01%. the minimum MAE (0.021 L h(-1)) and RMSE (0.028 L h(-1)) values were found in the SST k-omega low-Re corr. turbulence model and the minimum MAPE (1.068%) was found in the laminar turbulence model.

This study proposes a novel solar assisted absorption cooling (SAAC) system and performs its exergetic analysis and assessment. The system was designed, constructed and tested in Izmir, Turkey. Water was used as refrigerant in the system. The performance of the whole system along with its main components was assessed through exergy analysis method. The results obtained gave the exergy destruction rate, the exergy efficiency in various forms, the relative irreversibility and sustainability index in both charging and discharging processes. A parametric study was also undertaken to investigate the effect of the various dead (reference) state temperatures ranging from 30 degrees C to 42 degrees C with an interval of 4 degrees C on the entire system efficiency. In this context, the exergy efficiency of the whole system varied between 13.1 and 43.2% as the dead state temperatures increase from 30 degrees C to 42 degrees C. The highest relative irreversibility values of 66.1% and 34.6% belonged to the solar collectors and the absorption chiller in charging and discharging processes at a dead state temperature of 34 degrees C, respectively. (C) 2013 Elsevier B.V. All rights reserved.

The objective of this study was to evaluate the suitability of pumice stones, volcanic tuff and greenhouse shading net as alternative pad materials to the widely used and commercial one called CELdek. For this purpose, the tests were carried out at four levels of air velocity (0·6, 1·0, 1·3 and 1·6 m s−1) four levels of water flow rate (1·0, 1·25, 1·5 and 1·75 l min−1) and three levels of pad thickness (50, 100 and 150 mm). The tests were made at 30±1 °C and 40±1% relative humidity air conditions. The temperature of water flow was kept constant at 25±2 °C during the tests. According to the results of this study, it can be stated that the volcanic tuff pads are good alternatives to the CELdek pads at 0·6 m s−1 air velocity.