1. LABORATORY 3 Transient Thermal Behavior with Work and Heat Loss

2. Objectives Study thermal response of a system due to mechanical work input Model the thermal response as a first order system

3. Background Frictional mechanical work (Power) input Heat gain and loss System: Calorimeter Temp rise Figure 1. Schematic of the Calorimeter Arrangement

4. Background Heat loss  (Recall thermocouple physics) Controlling Equation:

5. Simplifications No heat loss No work input

6. 100 kΩ To A/D Converter +5 Volt Supply Thermistor Ceramic Resistance Temperature Device  R decreases as T increases  T (Celsius) = 17.58 V(t)– 18.73 (volts) ~100 kΩ

7. Typical Heating Data

8. Cooling Data

9. Thermocouple Dynamic Calibration T(  ) = 75 2/3 x 70 = Step  47 T(0) = 5 τ  7 – 2 = 5 sec t(0) = 2 sec

10. Time Constant

11. Linearized Temperature vs. Time