Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN: 9781305387102
Author: Kreith, Frank; Manglik, Raj M.
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Question
error_outline
This textbook solution is under construction.
Students have asked these similar questions
Oxy-acetylene torches can be used to cut or weld metal .Oxygen and acetylene are fed from separate compressed gas cylinders through pressure regulators to the torch where they are mixed and combusted .To estimate the amount of metal that can be cut or welded per unit volume of gas, the composition of the gases produced by combustion and heat produced by the combustion reaction must be determined .For this problem:
Define a closed system that can be used to calculate the heat produced
Define an open system that can be used to calculate the heat produced
List at least two intensive variables that are important in calculation
List at least two extensive variables that are important in the calculation
A child opens the door of the freezer that is turned off, to observe its operation. If the ambient temperature is 30°, what will be the behavior of the internal temperature of the freezer when it is opened and why?
a. does not change, since there is no material between the environment and the interior of the freezer for heat exchange
b. is increasing, because the convection between the environment and the air inside the refrigerator does not transfer heat from the outside to the center
c. does not change, since there is no contact between the surface of the meat and the external environment
d. increases, because sunlight falls on the meat, increasing the energy.
Then, when turning on the freezer again, it is observed that the back of the freezer gradually warms up, and remains warm during the operation of the machine. The amount of thermal energy emitted by the freezer must be:
a. equal to 0; the heating is due to a problem with the freezer
b. Less than the energy drawn from inside the…
Two inches of urethane foam will reduce heat loss close to 1000% when applied to a 2-inch diameter uninsulated steel pipe. Assume the pipe wall thickness is 0.25-inches, the pipe interior convective heat loss (hi) is 500 BTU/hr-ft2-oF, and the pipe outside convective heat loss ho 20 BTU/hr-ft2-oF, k steel is 25 BTU/hr-ft-oF, and k insulaton is 0.023 BTU/hr-ft-oF. (hint - calculate heat loss with and without insulation.
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- Industrial pipes One of the ways to keep a pipe warm is by means of a steam tracer, through which an electrical resistance is used around the pipe and in a helical shape throughout its diameter?arrow_forwardA conditioned space has a calculated heat loss at the design maximum heating day of 10,000 BTUs / Hr to maintain an interior temperature of 70 F. We will use a hydronic baseboard style convector to heat the space. The style we have chosen comes in standard lengths. At rated temperature and flow of hydronic heating fluid for each 1 foot of length the heater will add 750 BTUs /Hr to the room. What length of heater can just maintain the temperature on the worst day? For this example we are ignoring other sources of heat loss such as ventilation or drafts.arrow_forwardYou would like to use a pipe-based continuous flow hydroponic system. In this configuration, the roots of the strawberry plants are exposed to water that flows continuously through cylindrical pipes, driven by a pressure pump. The pipes are oriented horizontally so that the nutrient-containing water flows in the axial (x) direction. You are wondering whether this design is sufficient to support the needs of your strawberry plants. Your hydroponics system requires you to pay for the costs of the electricity used to heat the water that flows through the pipes. Strawberry plants grow best when their roots are exposed to water at a temperature of 25°C. The water that flows through the pipes is stored in a tank (inside height = 2 m), which sits on the ground outside of a greenhouse. In July, the average air temperature is Tair = 26°C, with heat transfer coefficient hair = 20 W/m2·K. The temperature of the ground underneath the water tank is Tground = 10°C. The heat capacity of water is…arrow_forward
- A pressure cooker cooks a lot faster than an ordinary pan by maintaining a higher pressure and temperature inside. The lid of a pressure cooker is well sealed, and steam can escape only through an opening in the middle of the lid. The pressure relief valve consists of a spring-loaded disk that is positioned over this opening. Consider that a certain portion of a pressure cooker is initially filled with water and put on top of a stove (State - 1). Heat is added just until the pressure relief valve opens (State 2). Heat continues to be added until all of the liquid disappears (State 3). Using the knowledge that you learned in the Thermodynamics-I Course, analyze the operation of this pressure cooker thermodynamically (i.e. find the intensive properties of water such as temperature, pressure and quality, mass of liquid water in the cooker, mass of water vapor that has passed through the pressure relief valve, and time passed for various stages of its operation). Operation and design…arrow_forwardA pressure cooker cooks a lot faster than an ordinary pan by maintaining a higher pressure and temperature inside. The lid of a pressure cooker is well sealed, and steam can escape only through an opening in the middle of the lid. The pressure relief valve consists of a spring-loaded disk that is positioned over this opening.Consider that a certain portion of a pressure cooker is initially filled with water and put on top of a stove (State - 1). Heat is added just until the pressure relief valve opens (State 2). Heat continues to be added until all of the liquid disappears (State 3).Using the knowledge that you learned in the Thermodynamics-I Course, analyze the operation of this pressure cooker thermodynamically (i.e. find the intensive properties of water such as temperature, pressure and quality, mass of liquid water in the cooker, mass of water vapor that has passed through the pressure relief valve, and time passed for various stages of its operation). Operation and design…arrow_forward4) One measure of the scale of a process is its throughputs of fuel or other input raw materials, e.g., lbs of coal per hour. Compare the coal throughputs for a small-scale experiment that uses 10 mg of coal in 6 seconds, and a single boiler in a large commercial-scale central-station electric generating plant. Assume: the commercial facility has a total output of 1,020 MW e supplied by three boilers of equal capacity; the boiler has a heat rate of (8,980 Btu th /hr)/(kW e ) based on fuel HHV, and fires coal with a gross heating value (i.e., HHV) of 14,000 Btu th /lb.arrow_forward
- 1. If the thermal conductivity increase the heat transfer coefficient will 2.The rate of evaporation at a given operation in an evaporator is more when a.there is a vacuum b.the operating pressure is high c.when the feed flowrate is high d.the operating pressure is low 3.In fluid, if the currents are set in motion by the action of mechanical device, the flow is independent of density gradient, the phenomenon is called a.heatexchanger behavior b.natural convection C.forced convection d.thermal conductionarrow_forwardChapter Va - 31 BOOK: ENGINEERING THERMOFLUIDS, M. MASSOUDarrow_forwardConsider a heat transfer situation. Heat flows from the hot item or area to the cold item or area. Describe this in terms of spontaneity.arrow_forward
- Can someone please help me with creating an excel spreadsheet to calculate heat transfer phenomenon from a cylindrical fuel rod to the coolant? The excel sheet needs to be able to calculate these 3 things: Heat generated in a fuel rod at a distance ‘r’ from the center; Total Heat generated in the Reactor; the maximum temperature in the fuel and the cladding surface temperature, for a fuel rod at a distance ‘r’ from the center. The fuel used in this will be UO2 and there is a thin layer of helium that will separate the fuel from the cladding material. The user input parameters will be: the thermal neutron flux at the core, thermal conductivity of fuel, thermal conductivity of helium, thermal conductivity of the cladding, thickness of the helium layer, thickness of the cladding, diameter of the fuel pellet, fuel rod location (r), Cylindrical Reactor Size, and the fuel enrichment. For the fluid the user input will be coolant temperature and the heat transfer coefficient.arrow_forward"For section 7, list the ONE PRIMARY way that heat transfers through this section. Section 7 involves heat moving through the solid outside wall, between the inside and outside surfaces of the outside wall."arrow_forwardHeat Engine you are an engineering consultant who has been tasked with providing power to a remote village. After some initial evaluation it was determined that a simple four-device heat engine with water as the working fluid is the best option to produce electricity at the location. Natural gas and wood are abundantly available as a fuel source and 400 kW of power is needed. Design a heat engine to meet the stated requirements.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning
Principles of Heat Transfer (Activate Learning wi...
Mechanical Engineering
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Cengage Learning
Understanding Conduction and the Heat Equation; Author: The Efficient Engineer;https://www.youtube.com/watch?v=6jQsLAqrZGQ;License: Standard youtube license