LABORATORY 3 Transient Thermal Behavior with Work and Heat Loss
Objectives Study thermal response of a system due to mechanical work input Model the thermal response as a first order system
Background Frictional mechanical work (Power) input Heat gain and loss System: Calorimeter Temp rise Figure 1. Schematic of the Calorimeter Arrangement
Background Heat loss (Recall thermocouple physics) Controlling Equation:
Simplifications No heat loss No work input
100 kΩ To A/D Converter +5 Volt Supply Thermistor Ceramic Resistance Temperature Device R decreases as T increases T (Celsius) = V(t)– (volts) ~100 kΩ
Typical Heating Data
Cooling Data
Thermocouple Dynamic Calibration T( ) = 75 2/3 x 70 = Step 47 T(0) = 5 τ 7 – 2 = 5 sec t(0) = 2 sec
Time Constant
Linearized Temperature vs. Time