Experimental and CFD Simulation of a Helico-Axial Pump

Multiphase flows are encountered in the majority of crude oil wells. Electrical Submersible Pumps (ESPs) are used to pump the crude oil in wells that do not have sufficient pressure head. Conventional ESPs are mixed or radial flow pumps which have limited gas handling capabilities. For handling high GVF (Gas Volume Fraction) fluids, advanced gas handlers (a type of ESP) were used in series before the conventional ESPs. These homogenize the flow and eliminate gas lock occurrence. The behavior of ESPs (Advanced Gas Handlers) under two phase flows was not widely understood. To better understand the behavior, a helico-axial pump capable of handling fluids up to 90% GVF has been investigated. Using the high pressure closed loop test facility at the Turbo Machinery Laboratory, a 4-stage helico-axial pump has been tested experimentally using water and air as test fluids for varying conditions such as inlet pressure, flow rate, GVF, and rotating speed. Performance maps of the pump along with vibrational characteristics have been obtained to identify the Best Efficiency Point (BEP) and stable operating regimes. The head degradation of the pump under two phase flow conditions as a function of stage has been obtained. From the head degradation results, the number of advanced gas handler stages to be used before conventional ESPs in an actual assembly has been identified to improve the total system efficiency when used in the field. Based on the experimental data, a new empirical model is developed to predict the stage by stage performance under multi-phase flow conditions. To understand the two-phase flow behavior in the pump, flow visualization was performed on a full scale single stage pump that was designed and built using transparent Polycarbonate material. Flow visualization was performed using a laser and a high speed camera. The visualization has provided much insight into how the flow goes through the pump: showing recirculation zones, back flow, vortices, and impeller diffuser blade interaction. The bubble diameter obtained from the flow visualization is being used as one of the inputs to allow two phase CFD Simulations. The efficiency of Advanced Gas Handlers is less than conventional ESPs. To better understand the flow behavior, 3-D single- and two-phase flow through the pump was modeled numerically using the commercial software ANSYS. The pump flow model was validated using the experimental data. From the single-phase simulations, regions of improvement were identified to increase the efficiency of the pump. Different diffuser designs were evaluated to improve the performance of the pump. Two-phase simulations are performed to study the homogeneity of the flow and to identify head degradation. Head degradation can be improved by identifying the regions where the phases tend to separate in the flow path and eliminating them

Experimental and CFD Simulation of a Helico-Axial Pump

Multiphase flows are encountered in the majority of crude oil wells. Electrical Submersible Pumps (ESPs) are used to pump the crude oil in wells that do not have sufficient pressure head. Conventional ESPs are mixed or radial flow pumps which have limited gas handling capabilities. For handling high GVF (Gas Volume Fraction) fluids, advanced gas handlers (a type of ESP) were used in series before the conventional ESPs. These homogenize the flow and eliminate gas lock occurrence. The behavior of ESPs (Advanced Gas Handlers) under two phase flows was not widely understood. To better understand the behavior, a helico-axial pump capable of handling fluids up to 90% GVF has been investigated. Using the high pressure closed loop test facility at the Turbo Machinery Laboratory, a 4-stage helico-axial pump has been tested experimentally using water and air as test fluids for varying conditions such as inlet pressure, flow rate, GVF, and rotating speed. Performance maps of the pump along with vibrational characteristics have been obtained to identify the Best Efficiency Point (BEP) and stable operating regimes. The head degradation of the pump under two phase flow conditions as a function of stage has been obtained. From the head degradation results, the number of advanced gas handler stages to be used before conventional ESPs in an actual assembly has been identified to improve the total system efficiency when used in the field. Based on the experimental data, a new empirical model is developed to predict the stage by stage performance under multi-phase flow conditions. To understand the two-phase flow behavior in the pump, flow visualization was performed on a full scale single stage pump that was designed and built using transparent Polycarbonate material. Flow visualization was performed using a laser and a high speed camera. The visualization has provided much insight into how the flow goes through the pump: showing recirculation zones, back flow, vortices, and impeller diffuser blade interaction. The bubble diameter obtained from the flow visualization is being used as one of the inputs to allow two phase CFD Simulations. The efficiency of Advanced Gas Handlers is less than conventional ESPs. To better understand the flow behavior, 3-D single- and two-phase flow through the pump was modeled numerically using the commercial software ANSYS. The pump flow model was validated using the experimental data. From the single-phase simulations, regions of improvement were identified to increase the efficiency of the pump. Different diffuser designs were evaluated to improve the performance of the pump. Two-phase simulations are performed to study the homogeneity of the flow and to identify head degradation. Head degradation can be improved by identifying the regions where the phases tend to separate in the flow path and eliminating them

From Pollution to Resource: Advancing Swine Waste Treatment in the USA

Concentrated animal feeding operations (CAFOs) have led to environmental challenges, specifically waste management. Swine CAFOs generate large amounts of waste, requiring proper treatment to avoid air and water pollution. Conventional waste management technologies, such as lagoon and spray field systems, do not prevent air and water pollution impacts. Research for the past few decades led to recommendations for waste treatment technologies superior to lagoons and spray fields. Private environmental sustainability initiatives focused on reducing greenhouse gas emissions in the food supply chain have implemented biogas digester projects for capturing methane in covered swine lagoons to reduce greenhouse gas emissions. However, research indicates that methane capture alone does not solve the broader pollution issues associated with lagoon and spray field systems still in use at these CAFOs to dispose of digested effluents. The Environmentally Superior Technologies (EST) initiative in North Carolina set public standards to eliminate waste discharge, reduce atmospheric emissions, and control odors and pathogens. Research has confirmed that technologies coupling solids separation with water treatments to remove volatile organic carbon, pathogens, and reactive forms of nitrogen can meet EST standards. A designated EST—the Super Soil System—substantially reduced odor by 99.9%; pathogens by 99.99%, nutrients (phosphorus and nitrogen) by \u3e90%, and heavy metals (cooper and zinc) by 99%. The ammonia emissions were reduced by 94.4% for the warm and 99.0% for the cool season with respect to a conventional lagoon system. Corresponding greenhouse gas emission reductions were 96.7%. Components of designated EST can be applied to retrofit covered lagoons and anaerobic digestion systems with significant environmental benefits. Recommendations are proposed, based on the collective experience with EST and current trends in animal production concentration, for environmentally safe technologies to handle excess manure produced in the USA

Chronic pain : a complex condition with a multi-tangential approach

Chronic pain is known as ongoing pain that lasts longer than three months with increasing healing time. It is approximated that 20% of adults of different sexes, races, and socioeconomic backgrounds fall victim to chronic pain. It is a result of several factors and can have lifelong effects. Pain is a complex matter to measure; therefore, the physician needs to understand the patient’s health state to create a management plan tending to each issue adequately. There are many complications of such pain, and it can interfere terribly with an individual’s quality of life. This article has reviewed the complex pathogenesis of chronic pain and the spectrum of non-pharmacologic modalities and pharmacological treatment options. It has also explored the efficacy of certain drugs and underlined the importance of nonpharmacological options such as physical exercise, cognitive therapy, and physical modalities to treat chronic pain and all the conditions that accompany this disorder