Mr. Subrata Chakrabarti serves as a Scientist at ISRO's Liquid Propulsion Systems Centre (LPSC), where he specializes in the design and development of advanced propulsion technologies. His work focuses on semi-cryogenic engines, contributing to the development of turbopumps and associated systems that are critical for next-generation launch vehicles.
With a background in mechanical engineering, Mr. Chakrabarti has been instrumental in addressing the challenges associated with high-thrust propulsion systems. His contributions include the development of pressure drop control regulators and solenoid actuators, which are essential for the precise control of propellant flow and engine performance. These innovations have applications beyond aerospace, offering insights into fluid dynamics and control systems relevant to various industrial processes.
Mr. Chakrabarti's expertise aligns with the themes of ECM 2025, particularly in areas concerning energy efficiency, system reliability, and advanced control mechanisms. His work exemplifies the integration of complex engineering principles to develop systems that are both robust and efficient, providing valuable perspectives for industries aiming to optimize energy usage and system performance.
In addition to his technical contributions, Mr. Chakrabarti is engaged in knowledge dissemination through publications and conferences, fostering collaboration between the aerospace sector and other engineering disciplines. His interdisciplinary approach underscores the importance of cross-sector innovation in advancing energy conservation and management practices.
Title: A brief overview of energy conversion efficiency in solenoid valves
Solenoid valves are the simplest form of electromagnetic actuators. They find wide and extensive usage in industrial applications like aerospace, defence, nuclear, automotive and appliance applications to name a few. These devices are best known for their very fast response time and repeatable operation which can be reproduced over a wide cyclic life often extending to a million cycles. In the aerospace sector, these valves act as propellant shut-off valve for satellite reaction control thrusters for attitude and orientation control over a period of approximately 12 to 15 years while the spacecraft operates in orbit. This kind of robustness is inbuilt in its design which is very simple. It generally contains a movable pole piece called the plunger which when actuated, would open the fluid flow passage and admit propellants to the downstream thruster leading to ignition and thrust generation. A complex energy transfer mechanism occurs whenever a solenoid valve is powered on. Input electrical energy which is provided by either a DC or AC supply gets converted to magnetic flux and then to mechanical energy. Normally losses associated with AC solenoids are eddy current power loss, solenoid copper power loss and ohmic power loss. The eddy current power loss is normally not considered for DC solenoids. It is reported that the opening response is juxtaposed to the energy conversion efficiency with the efficiency decreasing with the valve becoming faster at higher operating voltages. Effects of other variables are also well reported in literature. It is observed that most of the studies concerned with energy conversion efficiency report its dependence on factors external to the valve, like applied voltage. Studies reporting dependence on valve design features are few and far between. Also, this parameter comes into play mainly during the opening and closing transients and not during steady state operation since the valve has already opened and no further energy transfer to mechanical energy takes place
The energy conversion efficiency is seen to typically lie in the range 15 to 40 %. It assumes significance considering that these devices are often required to function in pulse width modulation (PWM) mode of operation requiring them to frequently open and close. In aerospace application while operating as a part of cold gas thrusters for example, these valves may be required to operate typically at a frequency of 50 Hz. In this application, frequent control correction requirements for making attitude and roll adjustments imply that the valves must open and shut frequently for admitting gaseous propellants for maintaining the orientation of an orbiting stage. Hence, it becomes imperative to find out the operating voltage where the energy conversion efficiency is highest. This would result in financial savings over a prolonged operational duration. A suitable operating voltage can be decided based on opening response and efficiency requirements after reconciling the two. In short, this offers an attractive area of interdisciplinary research where refinements in valve design and operating conditions can lead to savings and enhancement in design robustness.