Engineering topics
Publications and source records attributed to Malik, Sheharyar.
This work focused on designing, manufacturing, and testing a new particle flow control valve for use in particle-based CSP systems. Additionally, simulations were conducted to verify the results and validate the ability to predict the particle flow control of alternative designs.
Particle-based Concentrated Solar Power (CSP) systems most often utilize the state-of-the art slide gate mechanism for particle flow control. The slide-gate was found to have a sensitivity of 0.354 g/s-mm, a measure of mass flow rate over actuation position [1]. Particle-based CSP developers have noted that the slide gate is conducive to particle lodging, leaking, and difficulty actuating under particle pressure as well as differential expansion of the gate from thermal cycling. The goal of this work is to design, develop and test a novel particle flow control device that can operate without any hindrance from these shortcomings.
The next generation of Concentrated Solar Power (CSP) systems are utilizing solid particles as the heat transfer medium. The state-of-the-art particle flow control mechanism currently utilized is the slide-gate mechanism which functions by linearly actuating a gate across a tear-drop shaped opening. The sensitivity, which is a measure of the change in mass flow rate per unit movement of the slide-gate, is 0.354 g/s-mm[1]. The slide-gate’s main shortcomings include particle lodging and particle leakage between the plates, and difficulty actuating under the pressure from the particles. The goal of a new device is to minimize or eliminate these flaws. The new proposed device functions similar to a chuck mechanism in a drill where a rotation of an outer ring produces a change in outlet area through moving “jaws” diagonally. This mechanism aims to solve the issues of the slide-gate by having the jaws on the outside of the particle flow volume to reduce the probability of particle lodging, and the jaw tips are designed to overlap as they actuate to reduce particle leakage. Additionally, the vertical orientation of the device as well as the inclined movement of the jaws allows for easier actuation of the device under pressure. Experiments involving 3D printed prototypes have been carried out, producing a max mass flowrate of about 50 g/s and a sensitivity curve with the equation 𝑦 (𝑔/𝑠) = 0.0851𝑥^2(𝑔/𝑠−𝑚𝑚2) +3.6993𝑥(𝑔/𝑠−𝑚𝑚). These experiments validated the device’s capability to address the shortcomings of the slide-gate. Currently, an aluminum model of the device is being tested at room temperature, and a stainless-steel model is being developed to be tested at 700oC, which is the expected operating temperature of the CSP system. Furthermore, simulations are on-going to predict the mass flowrate of different device configurations at room and high temperatures.
Develop a new particle flow control mechanism that reduces operational difficulty at high temperatures
Within particle-based Concentrated Solar Power Systems (CSP), particles are the heat transfer medium, and therefore, the heat transfer effectiveness of these systems is reliant on their ability to effectively control particle mass flow rate. The vast majority of approaches for particle flow control in high temperature CSP is based on a slide-gate approach where a gate is linearly actuated across a tear-drop shaped opening. The slide-gate mechanism has a sensitivity of 0.354 g/s-mm, which is defined as the mass flow rate over the position of the gate. In the present work, we have designed and tested a new particle flow control mechanism with the potential for faster response times and different sensitivities than a slide gate approach enabling more control of particle flow. The new device enables flow control through moving jaws diagonally to change the outlet area. The new devices sensitivity value follows a quadratic curved as compared to the slide-gate’s linear slope over the same jaw movement. A larger sensitivity value is directly related to a quicker response time when utilizing the same actuator.
The submission is a two-page extended abstract. Within particle-based Concentrated Solar Power Systems (CSP), particles are the heat transfer medium, and therefore, the heat transfer effectiveness of these systems is reliant on their ability to effectively control particle mass flow rate. The vast majority of approaches for particle flow control in high temperature CSP is based on a slide-gate approach where a gate is linearly actuated across a tear-drop shaped opening. The slide-gate mechanism has a sensitivity of 0.354 g/s-mm, which is defined as the mass flow rate over the position of the gate. In the present work, we have designed and tested a new particle flow control mechanism with the potential for faster response times and different sensitivities than a slide gate approach enabling more control of particle flow.
Flow control within a particle-based Concentrated Solar Power (CSP) system is essential in determining the heat transfer coefficient, and therefore, the power generation capability of these systems. There are three areas where particle flow control is significant: the receivers, storage tanks, and particle-sCO2 heat exchangers. The focus of this paper is on designing a new mechanism to control the flow in the particle-sCO2 heat exchangers due to the simplicity and potential cost savings when compared to the other areas of interest. The goal is for this new design to have quicker response times in terms of particle flowrate than a slide gate or flow control valve, which are designs currently used. The design resembles that of a chuck mechanism within a drill where a rotation of the sleeve elicits movement of the jaws both vertically and horizontally to close the outlet area of the nozzle. Additionally, this design will utilize the current actuator that is already used within these heat exchangers to reduce the complexity of implementation. The jaws are designed to be closed at an angle of 76 ̊ which is just slightly steeper than the hopper leading to the mechanism. Furthermore, this design can be tuned to limit particle bridging and other particle flow phenomena that result in blockages. The prototypes were 3D printed out of polylactic acid (PLA) and scaled up to 100%, 200%, and 400% to be able to observe the velocity profiles of the mechanism more clearly. Experiments are performed with this prototype to compare the inlet and outlet mass flow rates at different configurations of the jaws. The particles used in these experiments are 0.3mm HSP 40/70 that are commonly used in particle-based CSP systems.