Theory and Design for Mechanical Measurements
6th Edition
ISBN: 9781118881279
Author: Richard S. Figliola, Donald E. Beasley
Publisher: WILEY
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Chapter 5, Problem 5.48P
A J-type thermocouple monitors the temperature of air flowing through a duct. Its signal is measured by a thermostat. The air temperature is maintained constant by an electric heater whose power is controlled by the thermostat. To test the control system, 20 measurements of temperature were taken over a reasonable time period during steady operation. This was repeated three times with the following results:
| Run | N | r[°c] | 5r[°C] |
| 1 | 20 | 181.0 | 3.01 |
| 2 | 20 | 183.1 | 2.84 |
| 3 | 20 | 182.1 | 3.08 |
The thermocouple itself has an instrument error with uncertainty ± I °C (95%) with v = 30. It has a 90% rise time of 20 ms. Thermocouple insertion errors are estimated to be ±1.2 °C (95%). What information is found by performing several replications? Identify the elemental errors that affect the system’s control of the air temperature. What is the uncertainty in the set temperature?
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A mercury thermometer, which has been on a table for some time, is registering the room
temperature, 50°F. Suddenly, it is placed in a 395°F oil bath. The following data are obtained
for the response of the thermometer. If after 10 seconds the thermometer reading is 176 F, determine the thermometer time constant.
Round off the final ans to whole number
Please show your complete solution and write readable.
A heat pump is an electrical device that heats a building by pumping heat in from the cold outside. In other words, it's the same as a refrigerator, but its purpose is to warm the hot reservoir rather than to cool the cold reservoir (even though it does both). Let us define the following standard symbols, all taken to be positive by convention:Th = temperature inside buildingTe = temperature outsideQh heat pumped into building in 1 day Qe = heat taken from outdoors in 1 dayW = electrical energy used by heat pump in 1 day
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Chapter 5 Solutions
Theory and Design for Mechanical Measurements
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Ch. 5 - Heat transfer from a rod of diameter D immersed in...Ch. 5 - Estimate the design-stage uncertainty in...Ch. 5 - Explain the critical dift'erence(s) between a...Ch. 5 - A displacement transducer has the following...Ch. 5 - Prob. 5.18PCh. 5 - For a thin-walled pressure vessel of diameter D...Ch. 5 - Suppose a measured normal stress contains three...Ch. 5 - Prob. 5.31PCh. 5 - The area of a flat, rectangular parcel of land is...Ch. 5 - Estimate the random standard uncertainty in the...Ch. 5 - Estimate the uncertainty at 95% confidence in the...Ch. 5 - One use for a GPS rangefinder is on the golf...Ch. 5 - A pressure measuring system outputs a voltage that...Ch. 5 - The density of a metal composite is to be...Ch. 5 - A temperature measurement system is calibrated...Ch. 5 - The power usage of a strip heater is to be...Ch. 5 - The power usage of a DC strip heater can be...Ch. 5 - A thermocouple is a temperature sensor made of two...Ch. 5 - Time variations in a signal require that the...Ch. 5 - A hand-held infrared thermometer from a well-...Ch. 5 - The pressure in a large vessel is to be maintained...Ch. 5 - The cooling of a thermometer (c.g., Exs. 3.3 and...Ch. 5 - A J-type thermocouple monitors the temperature of...Ch. 5 - The density of air must be known to within 0.5%....Ch. 5 - In pneumatic conveying, solid particles such as...Ch. 5 - A step test is run to determine the time constant...Ch. 5 - The acceleration of a cart down a plane inclined...Ch. 5 - The heat flux in a reaction is estimated by Q =...Ch. 5 - A comparative test uses the relationship R =...Ch. 5 - A sensitive material is to be contained within a...Ch. 5 - A geometric stress concentration factor, K,, is...Ch. 5 - In Problem 5.9, we assumed that the errors in die...
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