PROJECTS

 Developing Two-phase Flow through Complex Geometries 

Two-phase flows are found in a wide range of engineering applications and industries. For example; the design of steam generators, heat exchanges, refrigeration systems, and pipelines for gas and oil mixtures transport requires detailed two-phase heat transfer and pressure drop analyses. The complex nature of the two-phase flow, which is characterized by the existence of the deformable interfaces, turbulence, phase interaction, and compressibility of the gas phase, makes it difficult to obtain reliable flow models and consequently reliable solutions for many industrial problems. These complexities are aggravated when the two-phase passes through complex geometries such as valves, orifices, elbows and sudden area change that commonly exists in the multiphase systems. Additional complexity arise when the two-phase passes through multiple piping components located close to each other. Failures in many energy and oil and gas transportation systems occur in the developing two-phase flow regions in such geometries due to variety of degradation mechanisms such as flow accelerated corrosion, cavitation erosion, erosion corrosion, and liquid impact erosion. This severely affects both safety and reliability of these systems and sometime leads to fatalities and huge economic loss. These failure modes found to strongly depend on both heat and mass transfer characteristics which are affected by the two-phase flow redistribution, phase separation and the flow instabilities generated within the geometry of the flow passage. Currently, developing two-phase flow in these complex geometries is not fully understood. Therefore, this research program aims at understanding the fundamental behaviour of developing two-phase flow through complex geometries, especially through multiple piping components with close proximity to one another. The outcomes of this proposed research will result in developing reliable mechanistic models and strategies to predict, monitor or mitigate pertinent industrial problems. This will significantly enhance the sustainability of multiphase systems and will directly benefit the Canadian economy. In addition, with the scarce expertise in the area of multiphase flow, the provision of HQPs, with such unique expertise to the Canadian industry and academia is the applicant’s ultimate objective behind his research program. 

Pumping liquid metal multiphase fluid flow 

Adapting an efficient method for pumping gas-liquid metal two-phase flow can make liquid metal magnetohydrodynamics (LMMHD) power generation systems economically feasible. The gas-lift pump is designed to provide the pumping needed for the liquid metal recirculation in the LMMHD system. Also, a numerical simulation was performed in order to understand the behaviour of the gas-lift pump and be able to identify the best operational condition and/or optimize the two-phase pumping process. In addition, the data were compared to a 1-D drift flux model that predicted the performance of the pump within the loop. The numerical results were found to be in an agreement with the experiments within ± 25 % which is considered adequate for optimization and design purposes of two-phase flow system. The dual injection design was evaluated, and the axial injection mode was found to more efficient in providing the required pumping than radial mode. Moreover, the flow visualization of the two-phase flow patterns seen in the pump riser was captured both experimentally and numerically indicating a swirl-like motion that can potentially be used to enhance heat transfer in the actual operational setting. Also, the optimum condition for pumping was found to occur at slug-like flow structure in the riser. Both experimental and computational results were used to optimize the pump design and design the operational conditions needed to build a full scale LMMHD power generation loop. 

Smart Pumping Technology for Agriculture Applications 

Traditional agriculture uses 70% of the global fresh water supply as compared to hydroponics that only use 10% resolving the world-wide shortage demand for fresh water. However, these systems require large amounts of energy to operate. The challenges associated with high production cost, slim profit margins and the high cost of energy make it imperative to adopt such sustainable and economically viable technologies to maintain profitability. Reducing the total energy use and improving productivity is critical for the sector to expand. In this project, a smart pump that is able to circulate water as well as nutrients in vertical farms using 50-70% less energy will be developed. These smart pumps are operated only by air with no moving parts, no lubrication required, no noise or vibration involved. The detailed design of this smart pumping system, optimization of manufacturing processes and product durability tests will be completed for this technology. These smart pumps will be capable of monitoring and adjusting their operating parameters to adapt to system demand and allow the farm to operate efficiently and improve productivity and profitability as well as troubleshoot potential system problems. A fully functioning pumping system will be tested in real world operational for potential commercialization to the vertical framing industry. 

Capacitance Sensor Design for Void Fraction Measurements 

Two-phase gas and liquid flow are encountered in many industrial processes. Monitoring the conditions of the flow is critical for quality, efficiency and safety assurance. In this work, capacitance sensor probes are designed and constructed to measure the instantaneous bulk void fraction in a vertical triangular tube bundle. The sensor is installed inside an acrylic duct with vertical tubes to simulate a nuclear reactor cooler. The instantaneous signal generated from the capacitance sensor allows the calculation of the two-phase flow void fraction. A Finite Element Analysis was performed on the sensor using COMSOL 5.1 to evaluate the electric response and sensitivity of the sensor under different flow conditions. A simulation-based approach is used to calibrate and increase the accuracy of the void fraction measurement. Simulation results show that for bubbly flow, the normalized capacitance approach over predicted the void fraction by up to 30% in some cases. By using the simulation results to scale the normalized capacitance, the error is reducible up to 5%.  

Engineered Airlift Pump Design for Aquaponics and Aquaculture Industry 

 Aquaponics systems offer sustainable farming option to cultivate both fish and plants using a substantial less amount of fresh water compared to traditional agriculture. However, the limited commercial growth of these systems is mainly due to their low economic gain with their high energy requirements in addition to the inadequate research and engineering work on how to optimize their operation. Reducing the power consumption and understanding the operational challenges of these systems can help make this industry more viable for commercial production. In this project, a 2,700 litter tilapia-basil aquaponics system equipped with a set of smart sensors to monitor the water chemistry, energy and plant and fish growth is investigated. A new efficient airlift pump design was also used to provide water circulation along with aeration as an option to reduce the required energy for operation. The new design of the airlift pump found to provide the required dissolved oxygen while reducing the required energy by approximately 40%. Also, the airlift pump found to help in stripping dissolved carbon dioxide over the duration of experiment. Both plant and fish growth parameters were also recorded in order to validate the feasibility of integrating airlift pump in aquaponics.