CHAPTER 12-Q

docx

School

Centennial College *

*We aren’t endorsed by this school

Course

126

Subject

Mechanical Engineering

Date

Dec 6, 2023

Type

docx

Pages

Uploaded by DoctorIronDeer50

CHAPTER 12—FLOW CONTROL TRUE/FALSE 1. Flow rates of solids are determined by measuring the weight on a specified length of a conveyer belt during a given time period. 2. The differential pressure meter can be used to measure the flow rate of a liquid, but not a gas. 3. A rotameter can be used to provide a feedback signal for closed-loop control. 4. A positive displacement meter can be used to provide a feedback signal for closed- loop control. 5. In an electromagnetic flow detector, a voltage is induced into the flowing substance 6. Most volumetric flow rate measurements are taken using an inferred method. 7. A rotameter is capable of reading the flow rate of a liquid or a gas. 8. Positive displacement flow meters are physically rotated by the fluid to develop the readings. MULTIPLE CHOICE 1. Solids that float on liquids are referred to as __________. a. foam c. slurry b. buoyants d. contaminants 2. A flow rate that is too high can cause an undesirable __________. a. pressure c. both a and b b. heat d. none of the above 3. Keeping an accounting record of the quantity of a product transferred from one location to another is referred to as __________. a. procurement d. conveyer volume b. custody transfer e. commodity exchange c. accumulated goods 4. Volumetric flow rate of a liquid is doubled by doubling the __________. a. velocity of the fluid c. output of the pump in the system b. area of the pipe d. any one of the above 5. __________ are classified as fluids. a. Liquids c. Vapors b. Gasses d. All of the above 6. Which of the following conditions cause the density of a fluid to increase? 1

a. an increase in temperature d. a decrease in pressure b. a decrease in temperature e. both b and c c. an increase in pressure 7. The unit of measure which represents viscosity is called the __________. a. centimeter c. density b. poise d. weight 8. If the viscosity of a fluid increases, its ability to flow __________. a. increases b. decreases 9. If the viscosity of a gas increases, its ability to flow __________. a. increases b. decreases 10. If the velocity of the fluid pumped through a piping system is reduced, the Reynolds number __________. a. increases b. decreases 11. Which of the following terms identify the unit of measurement for flow? a. velocity c. volumetric flow rate b. differential pressure 12. Which factors can cause turbulent flow? a. The diameter of a pipe is increased. b. The flow rate is reduced. c. The temperature to which the fluid is exposed decreases. 13. The Reynolds number is reduced if __________. a. the diameter of the pipe is smaller d. a fluid with a lower density is used b. the viscosity of the fluid is larger e. all of the above c. the velocity of the fluid reduces 14. The larger the diameter of a pipe, the __________ the fluid to pass through. a. more difficult it is for b. easier it is for c. It depends on whether the fluid is a liquid or a gas. 15. In a differential pressure flow meter, the velocity of a fluid leaving the orifice plate is __________ the fluid that approaches it. a. less than c. the same as b. greater than 16. The __________ design is the best type of differential pressure flow meter to measure slurries. 2

a. orifice plate c. venturi tube b. flow nozzle 17. Positive displacement meters are powered by __________. a. an external energy source b. the fluid which flows through them 18. The __________ type of flow meter is the most common type of meter to measure the volume of fluid that flows. a. differential pressure c. velocity b. positive displacement 19. A mass flow meter uses a __________ to determine the flow. a. volumetric reading c. differential pressure reading b. weight reading 20. A Coriolis flow meter is a __________ type of flow meter. a. volumetric c. mass b. weight d. velocity 21. In a Coriolis flow meter, the angle at which the tube twists is __________ proportional to the amount of liquid which passes through it. a. directly b. indirectly 22. As the velocity of the fluid increases, the resistance of the unshielded thermistor sensor head in a thermal flow meter __________. a. decreases c. stays the same b. increases 23. In a vortex flow meter, the sensor placed downstream measures __________. a. constant pressure that is proportional to flow rate b. the magnitude of pressure developed by the vortexes that form c. the number of vortexes that form within a given time period 24. In a time of flight ultrasonic flow meter, the difference between the transmitted and received frequencies become __________ as the velocity of the fluid increases. a. smaller b. greater 25. The placement of a flow sensor should be __________ pipeline diameters from a geometric obstruction. a. 1 c. 10 b. 2 d. 20 26. Which type of flow meter does not use inferred readings to determine flow? a. differential pressure d. electronic b. positive displacement e. B or C c. velocity 3

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

27. Flow meters are often used to measure the amount of material that is being bought and sold. This application is known as __________. a. energy transfer c. relief b. custody transfer d. proportioning 28. The accuracy of many volumetric flow meters is influenced by changes in the pressure and/or temperature of the measurement fluid. This is because changes in pressure and temperature can change product __________. a. time constant c. integrity b. density d. pH 29. The formula Q=VA indicates that volumetric flow can be determined if two variables are known. These variables are A –the cross-sectional area of the pipeline, and V –the fluid __________. a. volume c. velocity b. venturi effect d. vena contracta 30. The unit of flow measurement is primarily based on __________. a. weight c. velocity b. flow rate 31. If the temperature of a liquid is lowered, it causes the Reynolds number to __________. a. increase b. decrease 32. A higher poise number indicates that the viscosity of a fluid has __________. a. increased b. decreased 33. Which of the following conditions cause the R number to decrease? a. increasing the velocity of the fluid b. using a fluid with a greater density c. reducing the pipe diameter to half its original size 34. The R number range of __________ is the transition range between laminar and turbulent flow. a. 2,000-3,000 b. 7,000-8,000 35. According to Bernoulli’s principle, as velocity of a fluid increases, pressure __________. a. increases b. decreases 36. There is __________ pressure on the incoming side of an orifice than on the outgoing side. a. less b. more 37. The primary element of a flow meter is the __________. 4

a. pressure detector on the inlet side of the orifice b. pressure detector on the outlet side of the orifice c. restriction 38. Which of the following restrictions are best used for measuring fluids that contain solid particles? a. orifice c. venturi b. flow nozzle 39. Which of the following restrictions provide the most accurate reading? a. flow nozzle b. venturi 40. Measurements taken by using the mass flow rate use __________ to determine the reading. a. volume b. weight 41. The faster the fluid flows through the tube of a Coriolis meter, the __________ it will twist. a. less b. more 42. The slower the conductive fluid flows through an electromagnet flow detector, the __________ the voltage induced. a. smaller b. greater 43. The faster the fluid flows through a thermal flow meter, the __________ heat is detected by the downstream thermistor. a. more b. less 44. What type of sensor is used to detect vortices in a vortex flow meter? a. temperature b. pressure 45. Flow meters based on the Doppler effect measure __________. a. sound c. capacitance b. magnetism 46. The sensor head __________ only measures the temperature of the fluid in the pipe. a. placed in the flow stream b. placed in the shielded recessed chamber 47. A flow meter that uses a rotor and a magnetic pick-up coil to count rotor revolutions is known as a __________ meter. a. Doppler c. turbine b. Faraday d. vortex 48. A vortex meter works on the principle that flow rate is proportional to the __________ of the vortices produced behind a bluff. a. length c. frequency b. width d. temperature 5

49. Primary advantages of direct-reading, mass flow meters such as the Coriolis meter include __________. a. non-invasive design b. immunity to changes in product density and other fluid properties c. immunity to changes in fluid pressure and temperature d. excellent accuracy e. all of the above 50. The greater the velocity the fluid flows through an orifice, the __________ the differential pressure that develops across it. a. less b. greater COMPLETION 1. Solids that float on liquids are called ____________________. 2. If the restriction is placed in a pipeline, the velocity of the fluid downstream of the restriction will ____________________ (increase, decrease) and the pressure on the outlet side of the orifice will ____________________ (increase, decrease). ANS: increase, decrease 3. The formula Q = VA indicates that volumetric flow can be determined if two variables are known. A represents ____________________ (accuracy, area), and V represents ____________________ (volume, velocity). PROBLEM 1. A conveyer system that transfers grain moves at a speed of 2 feet per second. If the system has a six-foot weighing platform, determine the mass flow rate if it measures 120 pounds. 2. If a conveyer system moves grain 100 feet per minute and the weighing platform is 5 feet long, what is the mass flow rate if the load cell measures 50 pounds? 6

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version