For my master thesis, I have investigated effects of ultrasonic waves on heat distribution in gaseous medium experimentally.

 

You can find publication by clicking on link below:

http://www.sciencedirect.com/science/article/pii/S1877042815038859

And you can find my master thesis(Turkish) below

My Master Thesis

As ultrasonic source I used 50W 28Khz piezoelectric transducer. I drive it at 20W power max.

To compare ultrasonic waves and flow generated by fan, I used 12 V small fan.

I used 50 ohm chrome-nickel resistance heater which I removed from hair dryer. I set it about 100W by dimmer.

To monitor heat distribution, I track temperature changes on A3 paper by FLIR A20 thermal camera.

I prepared two setups; “Open Setup” and “Closed Volume Setup” .

I placed heater on ultrasonic transducer, and place A3 paper vertically.

Closed volume setup is same with open setup, additionally enclosed with carton box and front surface is enveloped by transparent folio to watch temperature changes.

I have performed total 5 experiments on open and closed volume setups:

Open Setup Experiments :

1- Only heater runs
2- Both heater and ultrasound run

Closed Volume Setup Experiments:

1- Only heater runs
2- Both heater and ultrasound run
3- Both heater and fan run

 

I have used PIC based square wave signal generator and drive IRFP250N MOSFET by totem pole driver.

Totem pole driver is very important part of driving MOSFET in this experiment. Even though MOSFETs gate behave like capacitor, when frequency increases, gate  capacitor is charging-decharging and behaves like draining current. PIC itself is not able to supply such current.

totempole2

Totem Pole driver circuit with MOSFET IRFP250N

As Transformer, I used transformer removed from  250W SMPS computer power supply. Transformer has 220V input and 12V output. I used 12V as premier, 220V as seconder.

 

Transformer                                            Piezoelectric Transducers

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US.Transducer,Heater and Dimmer               Freq.Generator, 5V regulator, TotemPole, Mosfet+Heatsink,Transformer

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Open System Setup

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Closed Volume System Setup

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Experiment Results :

You can compare results on videos below. What I figure out is, Ultrasonic waves helps homogeneous heat distribution with respect to “no ultrasonic” experiment. Its seen more barely on closed volume setup experiment. Fan seems has much more effect then Ultrasonic waves, however, it may cause heat loss from some tiny holes on box. You can find more information in my publication or in my thesis.

Publication : http://www.sciencedirect.com/science/article/pii/S1877042815038859

Master Thesis : Click Here

Open Setup Experiment 1 : Just Heater ON, Ultrasonic OFF

 

Open Setup Experiment 2 :  Heater ON, Ultrasonic ON

 

Closed Volume System Experiment 1 : Just Heater ON, Ultrasonic OFF

 

Closed Volume System Experiment 2 : Heater ON, Ultrasonic ON

 

Closed Volume System Experiment 3 : Heater ON, Fan ON, No Ultrasonic

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