جستجوی مقالات مرتبط با کلیدواژه « Laboratory model » در نشریات گروه « مهندسی آب »

Protection of the downstream of culvert outlets against scour process, as a water conveyance structure, is a highly significant issue in design of culverts. In this study, the effect of bed litter length on downstream scour depth is investigated. For this purpose, experiments were carried out on the laminate with different lengths. According to the results, the particle landing at 22%, 33% and 66%, respectively, and the landing at particle landing of 2.5%, respectively. 15%, 20%, and 40% decreased particle depth by 20%, 25%, and 31%, respectively, indicating that bedding has a positive effect on decreasing downstream scour depth. The scour for the flooring considering the length of the layer showed that the scour depth decreases with the increase of the layer length due to the constant landing number.

Today, water desalination methods are of great importance in solving the freshwater crisis in the world, so that in recent years, the world's water desalination capacity has increased dramatically. Among them, the reverse osmosis membrane technology has been the most popular and the most commonly used. There are problems such as high energy consumption, high operating costs, and fouling in this method. The objective of this paper was to use reverse and forward osmosis membrane methods simultaneously in a hybrid reverse-forward osmosis setting, which enabled us to take advantage of the benefits of forward osmosis such as not being dependent on high hydraulic pressure, lower cost and less membrane fouling compared to reverse osmosis. Another objective of the study was to evaluate the permeate water production efficiency of desalination with this hybrid method. It is expected that using the hybrid method will reduce the required pressure for conducting reverse osmosis process to achieve a specified permeate flux, because it reduces cost and energy. An HRFO laboratory pilot with a capacity of 50 m3/day was designed and set up in the Hydraulic Lab of Shahid Chamran University of Ahvaz for running hybrid experiments. The design of the pilot was such that it could operate in both reverse osmosis and HRFO. HRFO experiments were carried out at pressures of 4.5 to 10.5 bar for Ahvaz urban water as feed solution, as well as NaCl as draw solution with a concentration of 2000 to 10000 mg/L via the experimental HRFO plant. It was found that adding the forward osmosis to reverse osmosis at the best situation (lowest pressure and highest concentration of draw solution) can increase the permeate water production efficiency of desalination by 55.12%. The best hybridization degree of these two methods was determined to be 64.5% for reverse osmosis and 35.5% for forward osmosis.

Protection of the downstream of culvert outlets against scour process, as a water conveyance structure, is a highly significant issue in design of culverts. In this study, the effect of bed litter length on downstream scour depth is investigated. For this purpose, experiments were carried out on the laminate with different lengths. According to the results, the particle landing at 22%, 33% and 66%, respectively, and the landing at particle landing of 2.5%, respectively. 15%, 20%, and 40% decreased particle depth by 20%, 25%, and 31%, respectively, indicating that bedding has a positive effect on decreasing downstream scour depth. The scour for the flooring considering the length of the layer showed that the scour depth decreases with the increase of the layer length due to the constant landing number.

There are currently several methods to prevent scouring the bridge base. These methods can be divided into two general categories. The first group is to increase the strength of the substrate materials against erosion, such as the use of a gobion, a rap ramp around the bridges, and the second one, by changing the pattern of the flow around the bases, reduces the strength of the erosion factors, which are the collars, And bridge bridges are examples of these methods. In this research, the experimental study of the impact of the bridge nose bridge on the scour depth reduction was considered. For this purpose, 22 experiments were carried out in the vicinity of the pollen and triangular nests at four angles (0.70,75,80.90) 215/0, 232/0, 261/0). According to the results of the experiment, the reduction of scour depth in the triangular nose support for different floats in all angles had the best performance in reducing the scour depth during the experiments.