A person is found dead at 5PM in a room whose temperature is 20°C. The temperature of the body is measured to be 25°C when found, Modeling the body as a 30-cm-diameter, 1.70-m-long cylinder and the heat transfer coefficient estimated to be 8 W/m2·K. and using the lumped system analysis as a rough approximation, estimate the time of death of the person.
Q: How does transient heat transfer differ from steady heat transfer? How does one-dimensional heat…
A:
Q: from the back side of the board to a medium at 37°C, with a heat transfer coefficient of 45 W/m²-K.…
A:
Q: The inner and outer surfaces of a 0.5-cm thick 2-m x 2-m window glass in winter are 10°C and 3°C,…
A: Calculate the area of window glass. Calculate the rate of heat transfer through the glass by…
Q: Consider a 1.2-m-high and 2-m-wide glass windowwith a thickness of 6 mm, thermal conductivity k =…
A: Given data Length of the plate L = 1.2 m width of the plate = 2 m thickness of the plate t= 6 mm…
Q: During a visit to a plastic sheeting plant, it was observed that a 60-m-long section of a 2-in…
A: Write the given information. Write the expression of the film temperature. Write the properties of…
Q: A 6-m-long section of an 8-cm-diameter horizontal hot-water pipe passes through a large room whose…
A:
Q: Q18: Heat is generated uniformly at a rate of 2.6 x10 w/m³ in a spherical ball (k = 45 W/m - "C) of…
A: Given Data: The rate of heat generation is q˙=2.6×106 W/m3. The thermal conductivity of the…
Q: In a production facility, large brass plates of 4-cm thickness that are initially at a uniform…
A: Given data: The thickness of the plate is t=4 cm=0.04 m The initial temperature of plate is…
Q: A 2-m × 1.8-m section of wall of an industrial furnace burning natural gas is not insulated, and the…
A: Answer: The thickness of the insulation that needs to be used is 4.68 cm.
Q: For heat transfer purposes, a standing man can be modeled as a 30-cm-diameter, 175-cm-long vertical…
A: Given: The convection heat transfer coefficient is h=10 W/m2 °C The diameter of the vertical…
Q: In a concentrated solar power plant, molten salt tank is used to store the thermal energy from the…
A:
Q: In a production facility, 3-cm-thick large brass plates (k =110 W/m·K, ρ= 8530 kg/m3 , Cp = 380…
A:
Q: The 4cm thick large copper plate, initially at a uniform temperature of 25 °C, is heated by passing…
A: Solution: Characteristic length of a infinitely large plate (δ)=L2=2cm Time in seconds…
Q: A 40-cm-long, 0.6-cm-diameter electric resistance wire is used to determine the convection heat…
A: Giiven A 40-cm-long, 0.6-cm-diameter the convection heat transfer coefficient = 254 surface…
Q: Q18: Heat is generated uniformly at a rate of 2.6 x10 W/m3 in a spherical ball (k = 45 W/m C) of…
A:
Q: Consider a 0.8-m-high and 1.5-m-wide double-pane window consisting of two 4-mm-thick layers of…
A:
Q: What is a semi-infinite medium? Give examples of solid bodies that can be treated as semi-infinite…
A: A semi-infinite solid : It is idealized body that has single plane surface & extends to infinity…
Q: Consider a sphere and a cylinder of equal volume made of copper. Both the cylinder and sphere 'are…
A: The answer is in next step
Q: A 5 m long section of a steam pipe whose outer diameter is 10 cm passes through an open space at…
A: Given data: The length of pipe, L=5 m. The diameter of the pipe, d=10 cm. The open space…
Q: Consider a 2-m-high electric hot-water heater thathas a diameter of 40 cm and maintains the hot…
A: Assumptions Heat transfer is in only radial direction. Conductivity of the foam insulation is…
Q: The roof of an electrically heated home is 9 m long, 12 m wide, and 0.50 m thick, and is made of a…
A: GIVEN DATA - AREA OF ROOF A=9*12m2 THICKNESS dx=0.50m Thermal conductivity k=0.8W/m'C T1=25'C T2=5'C…
Q: Consider heat transfer between two identical hot solid bodies and their environments. The first…
A: The lumped analysis system is mostly applied for the bodies which are allowed to cool in the air. A…
Q: A 5-cm-external-diameter, 10-m-long hot-water pipe at 80 deg C is losing heat to the surrounding air…
A: Diameter of pipe = 5 cm Length of pipe = 10 m Pipe temperature = 80 C Surface temperature = 5 C Heat…
Q: A person puts a few apples into the freezer at -13°C to cool them quickly for guests who are about…
A: To solve the above problem first of all we have to calculate , Biot number(Bi) and fourier…
Q: With a pressure of approximately 2 MPa, the two 6-cm-diameter, 18-cm-long aluminum bars (k = 176 W/m…
A:
Q: Consider a person standing in a room at 25°C. Determine the total rate of heat transfer and the heat…
A:
Q: A 6 cm diameter cylinder is initially at a temperature of 10 °C. Later, this cylinder was thrown…
A:
Q: Iron with a power rating of 1200 watts is left on the ironing board. The convective heat transfer…
A:
Q: Consider a cold aluminum canned drink that is initially at a uniform temperature of 4°C. The can is…
A:
Q: Consider a 1.2-m-high and 2-m-wide double-pane window consisting of two 0.023-mm-thick layers of…
A:
Q: An electric resistance space heater is designed such that it resembles a rectangular box 50 cm high,…
A: Consider the diagram shown below for the given heater. The mean film temperature is The properties…
Q: A 6-m-long section of an 9-cm-diameter horizontal hot-water pipe passes through a large room whose…
A:
Q: When a flat plate is subjected to uniform heat flux, how different are the relations compared to the…
A: To Explain : How different are the relations compared to the isothermal plate case. Formula used:…
Q: A person puts a few apples into the freezer at 15°C cool them quickly for guests who are about to…
A:
Q: Consider a room with a 1.8-m-high and 2.0-m-wide double-pane window consisting of two 4-mm-thick…
A:
Q: A 2-m x 1.8-m section of wall of an industrial furnace burning natural gas is not insulated, and the…
A:
Q: A person is found dead at 5 PM in a room whose temperature is 20°C. The temperature of the body is…
A:
Q: Consider a person whose exposed surface area is 1.7 m2, emissivity is 0.9, and surface temperature…
A:
Q: An aluminum pan whose thermal conductivity is 237 W/m*^ C has a flat bottom whose diameter is 20 cm…
A: Given-Data:- Thermal Conductivity=237Wm°CThickness of aluminium pan(L)=0.6cmDiameter of Aluminium…
Q: Q1: What is the difference between the forced convection and natural convection?
A: Both natural and forced convection are mode of heat tranfer in which motion of fluid takes place but…
Q: The temperature of a cylindrical tank containing liquid nitrogen is -10 ° C. Tank diameter is 16 cm.…
A:
Q: Consider a person standing in a breezy room at 20°C. Determine the total rate of heat transfer from…
A: Given: Room temperature is 20°C. Exposed area of the person is 1.6 m2. Surface temperature of the…
Q: A 40-cm-long, 800-W electric resistance heating element with diameter 0.5 cm and surface temperature…
A: The length of heating element = 40 cm = 0.4 m The diameter of heating element = 0.5 cm = 0.005 m The…
A person is found dead at 5PM in a room whose temperature is 20°C. The
temperature of the body is measured to be 25°C when found, Modeling the
body as a 30-cm-diameter, 1.70-m-long cylinder and the heat transfer coefficient estimated to be 8 W/m2·K. and using the lumped system analysis as a rough approximation, estimate the time of death of the person.
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
- 1.60 Two electric resistance heaters with a 20 cm length and a 2 cm diameter are inserted into a well-insulated 40-L tank of water that is initially at 300 K. If each heater dissipates 500 W, what is the time required for bringing the water temperature in the tank to 340 K? State your assumption for your analysis.3.16 A large, 2.54-cm.-thick copper plate is placed between two air streams. The heat transfer coefficient on one side is and on the other side is . If the temperature of both streams is suddenly changed from 38°C to 93°C, determine how long it takes for the copper plate to reach a temperature of 82°C.1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the convection heat transfer coefficient between the outer surface of the container and the air is 6.8 , the temperature of the air is 27°C, and the temperature of the surface of the sphere is –183°C, determine the rate of heat transfer by convection.
- A person is found dead at 5 PM in a room whose temperature is 20 °C. The temperature of the body is measured to be 25 °C when found, and the heat transfer coefficient is estimated to be h 8 W/m2 °C. Modeling the body as a 30-cm-diameter, 1.70-m-long cylinder, estimate the time of death of that person. The body can be modeled as a 30 cm diameter, 1.70-m-long cylinder. The thermal properties and body temperature of 37 °C. let The average human body is 72 percent water by mass, and thus we can assume the body to have the properties of water at the average temperature of (37 + 25)/2 = 31 °C; k = 0.617 W/m · °C, p= 996 kg/m³, and Cp=4178 J/kg · °CGround turkey was made into me at balls and refrigerated at 2 ° C before being deep fried. The diameter of each meat ball is 9cm. To make sure that the meat balls are safe to be consumed, they must be cooked over 70 ° C. Assume that the cooking oil is at a constant temperature of 180 ° C and has a heat transfer coefficient of 50 W/(m 2 ∙ K). The conductivity and specific heat of the ground turkey are approximated at 2 W/( m∙K ) and 4 kJ/( kg ∙ K) respectively. The density of the ground turkey is 500kg/ m 3 . a) During the deep- frying process, do you anticipate that each meat ball has a uniform temperature distribution throughout its volume? Please show calculation to support your answer (5 pts) . b) Please calculate the minimum time required for cooking (1 5 p ts). c) When served, what are the surface and center temperatures of each meat ball ( 15 pts).A steel plate having a thickness of 100 mm is suddenly exposed to a hot gas at 1000 °C in a furnace. One surface of the plate is heated while the other surface of the plate can be approximated to be adiabatic. The initial temperature of the steel plate is 20 °C. The thermal conductivity and thermal diffusivity of the steel plate are 34.8 W/m K and 0.555 x 10-5 m²/s respectively. The convective heat-transfer coefficient is 174 W/m²K. a) Determine the time necessary to raise the surface temperature of the steel plate to 500 °C. b) Determine the maximum temperature difference in the cross-section of the steel plate at the time evaluated in part a) above. c) Determine the heat energy transferred to the steel plate per unit wall surface area by the time evaluated in part a) above.
- A pipe 30 m long with an outer diameter of 75 mm is used to deliver steam at a rate of 2000 kg / hour. The vapor pressure is 198.53 kPa entering the pipe with a quality of 98%. The pipe needs to be insulated with a thermal conductivity of 0.2 W / (m K) so that the quality of the steam will only slightly decrease to 95%. The outer surface temperature of the insulation is assumed to be 25 ° C. Ignore resistance conductive of the pipe material and it is assumed that there is no pressure drop in the pipe. a. Determine the enthalpy of incoming vapor = AnswerkJ / kg. b. Determine the enthalpy of steam coming out = AnswerkJ / kg. c. Determine the vapor heat change / loss along the flow = Answerwatt. d. Specify the minimum required insulation thickness = Answercm.A pipe in a manufacturing plant is transporting superheated vapor at a mass flow rate of 0.3 kg/s. The pipe is 10 m long, has an inner diameter of 5 cm and pipe wall thickness of 6 mm. The pipe has a thermal conductivity of 17 W/m.K, and the inner pipe surface is at a uniform temperature of 120 °C. The temperature drop between the inlet and the exit of the pipe is 7 °C, and the constant pressure specific heat of vapor is 2190 J/kg.°C. If the air temperature in the manufacturing plant is 25°C, determine the heat transfer coefficient as a result if convection between the outer pipe surface and the surrounding air. T(r) = 120°C Superheated Air, 25°C r2 vapor r1 0.3 kg/s L = 10 m Tin-Tout = 7°CA pipe 30 m long with an outer diameter of 75 mm is used to deliver steam at a rate of 1500 kg / hour. The vapor pressure is 198.53 kPa entering the pipe with a quality of 98%. The pipe needs to be insulated with a thermal conductivity of 0.2 W / (m K) so that the quality of the steam will only slightly decrease to 95%. The outer surface temperature of the insulation is assumed to be 25 ° C. Ignore resistance conductive of the pipe material and it is assumed that there is no pressure drop in the pipe. a. Determine the enthalpy of incoming vapor = Answer kJ / kg. b. Determine the enthalpy of steam coming out = Answer kJ / kg. c. Determine the vapor heat change / loss along the flow = Answer watt. d. Specify the minimum required insulation thickness = Answer cm.
- Q2/ A 4-m-internal-diameter spherical tank made of 1.75-cm-thick stainless steel (k 15 W/m °C) is used to store iced water at 0°C. The tank is located in a room whose temperature is 35°C. The walls of the room are also at 35°C. The outer surface of the tank is black, and heat transfer between the outer surface of the tank and the surroundings is by natural convection and radiation. The convection heat transfer coefficients at the inner and the outer surfaces of the tank are 80 W/m2 °C and 10 W/m2· °C, respectively. Determine (a) the rate of heat transfer to the iced water in the tank and (b) the amount of ice at 0°C that melts during a l-h period. The heat of fusion of water at atmospheric pressure is hif 334 kJ/kg.A steel plate having a thickness of 100 mm is suddenly exposed to a hot gas at 1000 oC in a furnace. One surface of the plate is heated while the other surface of the plate can be approximated to be adiabatic. The initial temperature of the steel plate is 20 oC. The thermal conductivity and thermal diffusivity of the steel plate are 34.8 W/m K and 0.555 x 10-5 m2 /s respectively. The convective heat-transfer coefficient is 174 W/m2 K. a) Determine the time necessary to raise the surface temperature of the steel plate to 500 oC. b) Determine the maximum temperature difference in the cross-section of the steel plate at the time evaluated in part a) above. c) Determine the heat energy transferred to the steel plate per unit wall surface area by the time evaluated in part a) above. Use the conduction chartsA pipe 30 m long with an outer diameter of 75 mm is used to carry steam at a rate of 1000 kg / hour. The vapor pressure is 198.53 kPa entering the pipe with a quality of 98%. The pipe needs to be insulated with a thermal conductivity of 0.2 W / (m K) so that the quality of the steam will only slightly decrease to 95%. The outer surface temperature of the insulation is assumed to be 25 ° C. Ignore resistance conductive of the pipe material and it is assumed that there is no pressure drop in the pipe. a. Determine the enthalpy of incoming vapor = Answer kJ / kg. b. Determine the enthalpy of steam coming out = Answer kJ / kg. c. Determine the vapor heat change / loss along the flow = Answer watt. d. Specify the minimum required insulation thickness = Answer cm.