scholarly journals Uncertainty analysis of rising sewer models with respect to input parameters and model structure using Monte Carlo simulations and computational fluid dynamics

2021 ◽  
Author(s):  
Ahmed Khalil ◽  
Domenico Santoro ◽  
Damien J. Batstone ◽  
Christopher T. DeGroot
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Model Parameters ◽  
Model Structure ◽  
Mathematical Form ◽  
Homogeneous Surface ◽  
Simple Flows ◽  
D Model

Abstract Modelling conversion processes in sewers can help minimize odour and pipe corrosion issues, but model uncertainties and errors must be understood. In this study, the Wastewater Aerobic/Anaerobic Transformation in Sewers (WATS) model is implemented in two different frameworks; 1-D (CSTR-in-series) and computational fluid dynamics (CFD) to study the uncertainties due to model parameters and its mathematical form. The 1-D model is used to conduct uncertainty/sensitivity analysis using Monte Carlo simulations. Time-averaged outputs were represented using a general linearized model to quantify the importance of specific parameters. The sulfide formation rate per unit area of the biofilm is the most influential parameter. Parameters controlling anaerobic hydrolysis and fermentation are also significant. Uncertainty due to model structure is studied using CFD to explore the influences of non-homogeneous surface reactions and solids settling. These showed that the 1-D model provides a reasonable characterisation of the process for simple flows in pressure mains.

An Improved Computational Fluid Dynamics (CFD) Model for Erosion Prediction in Oil and Gas Industry Applications

2014 ◽  
Author(s):  
Deval Pandya ◽  
Brian Dennis ◽  
Ronnie Russell
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Surface Velocity ◽  
Particle Model ◽  
Model Parameters ◽  
Cfd Model ◽  
Erosion Model ◽  
Erosion Prediction ◽  
Erosion Models ◽  
Computational Fluid Dynamics Cfd

In recent years, the study of flow-induced erosion phenomena has gained interest as erosion has a direct influence on the life, reliability and safety of equipment. Particularly significant erosion can occur inside the drilling tool components caused by the low particle loading (<10%) in the drilling fluid. Due to the difficulty and cost of conducting experiments, significant efforts have been invested in numerical predictive tools to understand and mitigate erosion within drilling tools. Computational fluid dynamics (CFD) is becoming a powerful tool to predict complex flow-erosion and a cost-effective method to re-design drilling equipment for mitigating erosion. Existing CFD-based erosion models predict erosion regions fairly accurately, but these models have poor reliability when it comes to quantitative predictions. In many cases, the error can be greater than an order of magnitude. The present study focuses on development of an improved CFD-erosion model for predicting the qualitative as well as the quantitative aspects of erosion. A finite-volume based CFD-erosion model was developed using a commercially available CFD code. The CFD model involves fluid flow and turbulence modeling, particle tracking, and application of existing empirical erosion models. All parameters like surface velocity, particle concentration, particle volume fraction, etc., used in empirical erosion equations are obtained through CFD analysis. CFD modeling parameters like numerical schemes, turbulence models, near-wall treatments, grid strategy and discrete particle model parameters were investigated in detail to develop guidelines for erosion prediction. As part of this effort, the effect of computed results showed good qualitative and quantitative agreement for the benchmark case of flow through an elbow at different flow rates and particle sizes. This paper proposes a new/modified erosion model. The combination of an improved CFD methodology and a new erosion model provides a novel computational approach that accurately predicts the location and magnitude of erosion. Reliable predictive methodology can help improve designs of downhole equipment to mitigate erosion risk as well as provide guidance on repair and maintenance intervals. This will eventually lead to improvement in the reliability and safety of downhole tool operation.

A novel aerodynamic controllable roof for improving performance of INVELOX wind delivery system

2020 ◽  
pp. 0309524X2091098
Author(s):  
Ali Golozar ◽  
Farzad A Shirazi ◽  
Shahin Siahpour ◽  
Fardad N Khakiani ◽  
Kambiz Gaemi Osguei
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuzzy Control ◽  
Ground Level ◽  
Model Structure ◽  
Performance Curve ◽  
System Efficiency ◽  
Roof Structure ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

INVELOX is a patented structure designed to capture the incident wind from every direction, guide the collected wind to the ground level, and increase its velocity. A novel mechanism called aerodynamic controllable roof structure is introduced to improve the wind stream performance of INVELOX. The advantages of aerodynamic controllable roof structure are twofold: improving efficiency and preventing wind escaping the system. Using aerodynamic controllable roof structure, a performance curve is obtained that can improve the system efficiency. Wind speed and orientation and structural deflection are the parameters that direct the roof orientation. Fuzzy control is utilized in a model structure to control the roof movements using two servo motors. Computational fluid dynamics simulations are done to validate the performance and capability of the aerodynamic controllable roof structure mechanism. Results show that the fuzzy control is successful in controlling the roof orientation and the results from the simulation indicate that the efficiency of the system can be increased up to 12%.

scholarly journals A new sewage exfiltration model – parameters and calibration

2011 ◽  
Vol 63 (10) ◽  
pp. 2294-2299 ◽  
Author(s):  
Christian Karpf ◽  
Peter Krebs
Keyword(s):  
Waste Water ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Experimental Studies ◽  
Model Parameters ◽  
Potential Danger ◽  
Detailed Consideration ◽  
Sewer Systems ◽  
The Law ◽  
Groundwater Infiltration

Exfiltration of waste water from sewer systems represents a potential danger for the soil and the aquifer. Common models, which are used to describe the exfiltration process, are based on the law of Darcy, extended by a more or less detailed consideration of the expansion of leaks, the characteristics of the soil and the colmation layer. But, due to the complexity of the exfiltration process, the calibration of these models includes a significant uncertainty. In this paper, a new exfiltration approach is introduced, which implements the dynamics of the clogging process and the structural conditions near sewer leaks. The calibration is realised according to experimental studies and analysis of groundwater infiltration to sewers. Furthermore, exfiltration rates and the sensitivity of the approach are estimated and evaluated, respectively, by Monte-Carlo simulations.

Sign in / Sign up

Export Citation Format

Share Document