Ask Question, Ask an Expert

+1-415-315-9853

info@mywordsolution.com

Ask Mechanical Engineering Expert

Problem 1

Provide short answers to the following problems:

a) What the essential condition for a heat transfer process to occur?

b) What is a differentiation between the steady state conditions and the thermal equilibrium state?

c) Is it probable for the steady state temperature profile in a plane wall to be nonlinear at steady state? If yes, provide one ex.

d) Why do you feel cooler throughout a windy day than throughout a calm day even though the air temperature is the same?

e) Why it is more likely to get burn through putting a bare hand in boiling water at 100oC then into hot air at 200oC?

f) What is a temperature gradient in an object sitting in a room in that the temperature is maintained constant after a sufficiently long time?

g) Is it probable that the surface temperature of the object from part f) to be different than the room air temperature? If yes, please elucidate why?

h) What is the chief reason for a ground frost (air temperature is greater than zero)? For a given air temperature, is ground frost more likely to occur at windy or calm conditions?

i) What is a differentiation between and opaque and semitransparent object?

j) What is the chief reason for the surfaces of different objects to be dissimilar when they exposed to sunlight?

k) What is the differentiation between the closed and open systems?

l) What is the inherent differentiation between application of conservation of energy over a time interval and at an instantaneous of time?

m) Why the form of the energy balance for a surface of an object at stable and uneven state conditions is the same?

n) What is the main reason irreversible operation of the actual heat engines?

o) What is the result of the power output of the actual heat engine on its efficiency? Please describe.

Problem 2

An experiment to find out the convection coefficient allocated with airflow over the surface of a thick stainless steel casting includes insertion of thermocouples in the casting at distances of 10 mm and 20 mm from the surface.  When the experiment was performed in a well insulated air duct so that the temperature of the walls surrounding the steel surface was the same as the air temperature, the thermocouples evaluated the temperatures of 50°C and 40°C in the steel, correspondingly, when the air and the surrounding wall temperatures were 200oC.

a) If the steel has a thermal conductivity of 15 W/m2K and surface emissivity of 0.95, what is the convection coefficient among the steel and hot air?

b) What are the contributions of the convective and radiation heat fluxes to the steel casting?

In the repeated experiments the duct insulation was removed and even although the hot air temperature was the same as before, i.e., 200oC, the surrounding walls temperature dropped to 20oC. As a consequence the steady state heat flux to the steel casting dropped by 13.3% compared to the first experiment.

c) Supposing the same convection coefficient as the value computed in part a), what would be the temperatures evaluated by the thermocouples?

d) Assume that the steel casting was well insulated from all sides except for surface from which the distance to thermocouples is evaluated. Supposing the same convection coefficient as the value computed in part a), what would be the temperatures of the thermocouples when:

i) The experiment is performed in the well insulated duct at T∞ = Tsurr = 200oC?
ii) The experiment is performed in non-insulated duct at T∞ = 100oC and Tsurr = 20oC?

Mechanical Engineering, Engineering

  • Category:- Mechanical Engineering
  • Reference No.:- M91070

Have any Question? 


Related Questions in Mechanical Engineering

Projectdesign a tube bank that will increase the

Project Design a tube bank that will increase the temperature of a 1200 CFM flow of air from 35°F to 100°F. Assume a constant pressure of 1atm. Each tube will have a diameter of 0.5in and a length of 24in. The tube confi ...

Mathematical modelling and analysis assignment - framework

Mathematical Modelling and Analysis Assignment - Framework Design A framework of pin jointed members has to be designed to support an emergency sluice gate in a tidal barrage wall. The gate is 1.0m high, 1.0m wide and it ...

A water-filled u-tube manometer is used to measure the

A water-filled U-tube manometer is used to measure the pressure inside an air tank. The water level in the U-tube on the side connected to the tank is 5 ft above the base of the tank. The water level in the other side of ...

You have been introduced to a number of different tools

You have been introduced to a number of different tools that can be used to help IE's and MfgE's analyze and develop solutions to make processes more effective and efficient. Watch the video located at http://www.iienet2 ...

A compute the intrinsic gate delay of the nmost given in

(a) Compute the intrinsic gate delay of the nMOST given in the above problem and also in section 661 at the biasing condition given above. (b) Compute the intrinsic power-delay product. (c) Does the load resistor increas ...

1 determine the capillary rise for a water-air-glass

1. Determine the capillary rise for a water-air-glass interface at 40°C in a clean glass tube having a radius of 1 mm. 2. Determine the difference in pressure between the inside and outside of a soap film bubble at 20 °C ...

Instead of the perturbation being switched linearly it was

instead of the perturbation being switched linearly, it was switched on and off exponentially and slowly, the switching off commencing long after the switching on was complete. Calculate the probabilities, long after the ...

Chemistry buildings built to code require a great deal of

Chemistry buildings built to code require a great deal of ventilation, which necessitates a delicate air-handling system to balance the air lowing into the building and the air lowing out. For example, if the air low out ...

As can often be seen in a kitchen sink when the faucet is

As can often be seen in a kitchen sink when the faucet is running, a high-speed channel flow (v 1 , h 1 ) may ''jump'' to a low-speed, low-energy condition (v 2 , h 2 ). The pressure at sections 1 and 2 is approximately ...

Invent a structure that can completely eliminate the narrow

Invent a structure that can completely eliminate the narrow gate effects. This is known as the fully recessed stepped oxide (FROSOX) whose sidewall oxide is thicker than the gate oxide and they are connected by a step or ...

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

Section onea in an atwood machine suppose two objects of

SECTION ONE (a) In an Atwood Machine, suppose two objects of unequal mass are hung vertically over a frictionless

Part 1you work in hr for a company that operates a factory

Part 1: You work in HR for a company that operates a factory manufacturing fiberglass. There are several hundred empl

Details on advanced accounting paperthis paper is intended

DETAILS ON ADVANCED ACCOUNTING PAPER This paper is intended for students to apply the theoretical knowledge around ac

Create a provider database and related reports and queries

Create a provider database and related reports and queries to capture contact information for potential PC component pro

Describe what you learned about the impact of economic

Describe what you learned about the impact of economic, social, and demographic trends affecting the US labor environmen