# MBU - Heat Transfer in Structures

MigrationCheck-Heat Transfer in Structures

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For System B (“Forced Air Cooling”), at a time of 0.5 seconds, what is the maximum temperature for the stent? Choose the nearest option. (Hint: Use Temperature result object)

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In System A (“Warm Day”), at what rate does heat flow from the ignited fuel into the engine assembly? [Hint: heat flowing into the engine is equal to the reaction due to the Convection boundary condition applied on the inner surfaces]

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For the current mesh that is used for this analysis, what is the order of the elements used?

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In System B, what is the minimum temperature attained by any portion of the bolts? Consider all the bolt heads, the shanks and the nuts. (71.637)

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When applying a Convection boundary condition, which Scoping Methods are available in Ansys Mechanical? Select the two best answers.

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If we want a finer mesh in a certain region of the model, clicking on which of the following options will allow us to do that?

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Which of the following are boundary conditions available in Ansys Mechanical? Select the three best options:

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The melting temperature of Silicon is about 1400 °C. Based on your analysis, is the gasket safe from melting?

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In System A (“Warm Day”), what is the minimum temperature of all of the bolts? Consider all the bolt heads, the shanks and the nuts.

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In System B (“Cold Day”), what is the heat flow rate leaving the engine assembly (i.e. from outer surfaces of the assembly to the surrounding air)? [Hint: heat flowing out of the engine is equal to the reaction due to the Convection boundary condition applied on the outer surfaces.]

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In System B (“Cold Day”), what is the maximum temperature of the entire assembly?

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In System B (“Cold Day”), what is the maximum of the Gasket part?

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In System A (“Warm Day”), where does the minimum temperature occur in the assembly?

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In System A (“Warm Day”), where does the maximum temperature occur in the assembly?

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In System A (“Warm Day”), what is the maximum temperature of the Gasket part?

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In System A (“Warm Day”), what is the minimum temperature of the entire assembly?

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In System A (“Warm Day”), what is the maximum temperature of the entire assembly?

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For both analyses, if the number of elements across the stent thickness is reduced to 1, how does it affect the cooling down time? (Hint: Set “Sweep Num Divs: 1” under Mesh > Sweep Method > Definition)

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Compare the results of System A (“Water Cooling”) with System B (“Forced Air Cooling”). How much faster does it take for the stent to cool below 21 °C in water as compared to forced air? Choose the best option. (Hint: Use Temperature result objects)

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For System B (“Forced Air Cooling”), at what time does the stent reach a maximum temperature of 25 °C? Choose the closest option. (Hint: Use Temperature result object)

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For System A (“Water Cooling”), at time of 0.25 seconds, what is the temperature on the stent? Choose the nearest option. (Hint: Use Temperature result object)

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For System A (“Water Cooling”), how much time does it take for the stent to cool to 100 °C? Choose the closest option. (Hint: Use Temperature result object)

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For both analyses, what is the final temperature of the stent at end of the simulation? Select the best answer.

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For both analyses, the stent starts cooling down from what temperature?

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For both analyses, what is the ending time for these simulations?

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For these simulations, why is Transient Thermal analysis used instead of Steady-State Thermal analysis? Select the best option.

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Calculate the approximate amount of radiative heat flow rate lost to the ambient environment in System C (“Open Door with Food”) by subtracting the heat flow rate of the exterior Convection boundary condition from ~1000W of input power. Recall that input power is our internal heat generation multiplied by the volume of the heating element.

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Ignore the interior convective heat transfer, as we have done in this simulation, and compare the maximum temperature of the food in System C (“Open Door with Food”) with the maximum temperature of the food in System A (“Closed Door with Food”). Which best reasonable conclusion can be drawn?

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What is the ratio of the maximum temperature of the food in System C (“Open Door with Food”), with the maximum temperature of the food in System A (“Closed Door with Food”).

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In System C (“Open Door with Food”), the maximum temperature of the heating element is _____.

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In System C (“Open Door with Food”), the maximum temperature of the food is _____.

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In System B (“Food Wrapped in Foil”), compare the absorbed radiative heat flow rate of the food (Emitted Radiation) to the net radiative heat flow rate (Outgoing Net Radiation) of the heating element. What fraction of the heat flow rate from the heating element is being absorbed by the food? (Recall that absorbed radiation = emitted radiation for bodies in thermal equilibrium.)

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In System B (“Food Wrapped in Foil”), the food with the aluminum foil has a low emissivity and hence high reflectivity. What is the reflected heat flow rate (Reflected Radiation) of the food?

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In System B (“Food Wrapped in Foil”), the food with the aluminum foil has a low emissivity and hence absorptivity. What is the absorbed heat flow rate (Emitted Radiation) of the food? (Recall that absorbed radiation = emitted radiation for bodies in thermal equilibrium.)

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In System B (“Food Wrapped in Foil”), the maximum temperature of the heating element is _____.

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In System B (“Food Wrapped in Foil”), the maximum temperature of the food is _____.

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In System A (“Closed Door with Food”), compare the absorbed radiative heat flow rate of the food (Emitted Radiation) to the net radiative heat flow rate (Outgoing Net Radiation) of the heating element. What fraction of the heat flow rate from the heating element is being absorbed by the food? (Recall that absorbed radiation = emitted radiation for bodies in thermal equilibrium.)

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The food has a high emissivity and hence low reflectivity. In System A (“Closed Door with Food”), what is the reflected heat flow rate (Reflected Radiation) of the food?

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The food has a high emissivity and hence absorptivity. In System A (“Closed Door with Food”), what is the absorbed heat flow rate (Emitted Radiation) of the food? (Recall that absorbed radiation = emitted radiation for bodies in thermal equilibrium.)

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The grill is a shiny metal and has low emissivity. In System A (“Closed Door with Food”), what is the reflected heat flow rate (Reflected Radiation) of the grill?

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In System A (“Closed Door with Food”), the grill is a shiny metal and has low emissivity. Thinking about this and the equation $\tau+\alpha+\rho = 1.0$ with transmissivity $\tau$ = 0, what is the reflectivity ($\rho$) of the grill.

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In System A (“Closed Door with Food”), looking at the temperature distribution on the food body only, why does temperature distribution show the food is hotter on the +Y side versus the –Y side.

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In System A (“Closed Door with Food”), what is the reflected radiative heat flow rate (Reflected Radiation) of the heating element?

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In System A (“Closed Door with Food”), what is the net radiative heat flow rate (Outgoing Net Radiation) of the heating element?

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In System A (“Closed Door with Food”), the heat flow rate due to convective losses is _____.

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In System A (“Closed Door with Food”), the maximum temperature of the heating element is ____.

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In System A (“Closed Door with Food”), the maximum temperature of the food is _____.

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In System B (without Heat Sink), which laptop component has the highest temperature in the simulation?

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In System A (with Heat Sink), which laptop component has the highest temperature in the simulation?

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In System A (with Heat Sink), the heat sink and the microprocessor are considered to be in perfect thermal contact. What does this imply? Select 2 best answers.

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What are the units for Internal Heat Generation? Select 2 best answers.

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How would mesh refinement influence the analysis? Select 2 best answers.

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Select the statement that is true for any steady-state thermal system.