APPLICATION OF COMPUTATIONAL FLUID DYNAMICS FOR THE EVALUATION OF FLOW DISTRIBUTION IN WASTEWATER TREATMENT PLANTS
DESIGN Computational Fluid Dynamics (CFD) is a computer based technique that solves fluiddynamic problems using numerical method solutions for the fundamental governingequations. This recent technique has been developed with the creation of more powerfulcomputers capable of processing complex numerical methods. CFD has been used in theaerospace and automotive industries since the 1970s.
CFD has the advantage of use fullscale models and evaluate the results easily and accurately, reducing time and costs.However, in the environmental and wastewater industries this technique has beenrecently used. In this research CFD is applied in the wastewater treatment plant designfor the
evaluation of a flow distribution in a disinfection system. The flow has to bedistributed in three UV units without exceeding the maximum flow of operation of theUV unit and ensure an adequate disinfection of the water.
To verify the applicability of CFD to solve this case it was necessary to examine a
verification case to confirm theaccuracy of the CFD technique applied for this general application. The virtual modelsused were created full scale and considering the geometry and flow characteristics of thereal cases.
The results obtained from the verification case indicate good potential of CFDapplication. Also, it was found that the turbulent/laminar ratio is a variable that affects theresults and has to be considered for simulations in other cases. The case of study was simulated under the different operational conditions that will occur in the system.
The results obtained from the case of study showed an even flow distribution in the differentcases evaluated and also, that the influence of the turbulent/laminar ratio decreased withthe flow and consequently with the velocity inside the tank. Based on the accuracy of CFD in the verification case it is concluded that the flow rate distributed in the UV unitswill never exceed the maximum acceptable value. For future research, it is recommendedto compare the results of the case of study with the system when is in operation. This research proved that CFD can be applied for evaluation of the systems, and based on thisit is recommended to use it further for the design of structures.
Author: Marianna Novellino