Gürfidan, Mehmet Gökalp
Pressure regulator is used for regulating high upstream pressure to required low downstream pressure. It is especially an important component for space applications where an accurate pressure control is vital, and failure to do so can cause mission failure. In this thesis a novel pressure regulator design is modeled that eliminates the inherent steady state error of purely mechanical pressure regulator by introducing cascaded electromechanical actuator. Dynamic components of the proposed hybrid pressure regulator are explained and mathematically modeled. Three system models are derived, namely nonlinear system model, simplified nonlinear model and linearized model. PID controller is designed for the actuator. Finally, hybrid pressure regulator is simulated using Matlab-Simulink with different operation scenarios with and without fault injection, and results are compared with a traditional mechanical pressure regulator having same design parameters.


Modeling and Experimental Study of Newtonian Fluid Flow in Annulus
SORGUN, Mehmet; Ozbayoglu, M. Evren; Aydın, İsmail (2010-09-01)
A major concern in drilling operations is the proper determination of frictional pressure loss in order to select a mud pump and avoid any serious problems. In this study, a mechanistic model is proposed for predicting the frictional pressure losses of light drilling fluid, which can be used for concentric annuli. The experimental data that were available in the literature and conducted at the Middle East Technical University-Petroleum Engineering (METU-PETE) flow loop as well as computational fluid dynamic...
Modeling, analysis, and screening of cyclic pressure pulsing with nitrogen in hydraulically fractured wells
Artun, Emre; Khoei, Ali Aghazadeh; Köse, Kutay (Springer Science and Business Media LLC, 2016-7-19)
Cyclic pressure pulsing with nitrogen is studied for hydraulically fractured wells in depleted reservoirs. A compositional simulation model is constructed to represent the hydraulic fractures through local-grid refinement. The process is analyzed from both operational and reservoir/hydraulic-fracture perspectives. Key sensitivity parameters for the operational component are chosen as the injection rate, lengths of injection and soaking periods and the economic rate limit to shut-in the well. For the reservo...
Predicting Frictional Pressure Loss During Horizontal Drilling for Non-Newtonian Fluids
SORGUN, MEHMET; Ozbayoglu, M. E. (Informa UK Limited, 2011-01-01)
Accurate estimation of the frictional pressure losses for non-Newtonian drilling fluids inside annulus is quite important to determine pump rates and select mud pump systems during drilling operations. The purpose of this study is to estimate frictional pressure loss and velocity profile of non-Newtonian drilling fluids in both concentric and eccentric annuli using an Eulerian-Eulerian computational fluid dynamics (CFD) model. An extensive experimental program was performed in METU-PETE Flow Loop using two ...
Numerical modeling of counter-current spontaneous imbibition during underbalanced drilling
Naseri, Masoud; Sınayuç, Çağlar (2012-09-10)
Mud solid and filtrate invasion are the most common causes of formation damage during overbalanced drilling (OBD), which is a method of drilling in which the wellbore pressure remains greater than formation pressure. During the past ten years, underbalanced drilling operations (UBD), which can be defined as a drilling method in which the wellbore pressure is less than formation pressure, has been growing due to their applications such as prevention of lost circulation, reduction of filtration lost in natura...
Dynamic response analysis of the machine foundations on a nonhomogeneous soil layer
Aşık, Mehmet Zülfü (1999-01-01)
Real modulus of elasticity of the soil usually increases with the depth of the soil due to the increase in overburden pressure. Therefore, incorporation of the effect of the soil inhomogeneity in the formulation to obtain the response of the machine foundations is an important and a necessary step. In this paper, equations that govern the dynamic behavior of the machine foundations and consider the inhomogeneity of the elastic foundation, particularly for Gibson type soil are derived by using variational pr...
Citation Formats
M. G. Gürfidan, “DESIGN AND MODELLING OF A HYBRID PRESSURE REGULATOR,” M.S. - Master of Science, Middle East Technical University, 2022.