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Identification of ultrasonic frequency for water mist generation using piezoelectric transducer

Senthil Murugan S., Vijayakumar P.

Archives of Materials Science and Engineering

2017

Vol. 83, nr 2

74--78

Purpose: Water is the most commonly used medium for fire extinguishing. It is both cheap and has high latent heat of evaporation. But the volume of water required for extinguishing the fire is significantly high, this in turn increases the amount of water stored. This can be reduced significantly by improving the efficiency of the extinguishing action by fire suppression. Water mist fire suppression system, Water mist fire extinguisher, fire hydrant are some of the commonly available methods for fire extinguishment process. This paper is about investigation on ultrasonic frequency for water mist generation without pressurized system. Design/methodology/approach: This technique helps reduce the usage of water required for fire extinguishment to a minimum level. Here H-bridge circuit has been designed with piezoelectric transducer which will operate at various frequency range (0 to 3 MHz). The developed model has been used to predict the minimum frequency required for water mist formation, which is about 2 MHz. Findings: An electrical circuit with h-bridge circuit and piezoelectric transducer has been specifically designed for water mist formation using ultrasonic vibrator has been fabricated. It is a tunable frequency circuit. The tunable frequency range various up to maximum of 3 MHz. From the above experimentation it has been identified that minimum 2 MHz Frequency is required for water mist formation in the water reservoir. Future research in this technique for water mist formation with high rating and increase in number of PET could provide better results. Fine water droplet is also possible with high rating frequency. Research limitations/implications: The developed model has been used to predict the minimum frequency required for water mist formation, which is about 2 MHz. These results will be useful in optimizing the water mist suppression system by varying the frequency and distance from the flame.

A Comparative Study of PID Controller Tuning Using GA, EP, PSO and ACO

Nagaraj B., Vijayakumar P.

Journal of Automation Mobile Robotics and Intelligent Systems

2011

Vol. 5, No. 2

42-48

Proportional - Integral - Derivative control schemes continue to provide the simplest and effective solutions to most of the control engineering applications today. How ever PID controller are poorly tuned in practice with most of the tuning done manually which is difficult and time consuming. This article comes up with a hybrid approach involving Genetic Algorithm (GA), Evolutionary Pro gramming (EP), Particle Swarm Optimization (PSO) and Ant Colony Optimization (ACO). The proposed hybrid algorithm is used to tune the PID parameters and its per formance has been compared with the conventional me thods like Ziegler Nichols and Cohen Coon method. The results obtained reflect that use of heuristic algorithm based controller improves the performance of process in terms of time domain specifications, set point tracking, and regulatory changes and also provides an optimum stability. Speed control of DC motor process is used to assess the efficacy of the heuristic algorithm methodology