Ask Question, Ask an Expert

+1-415-315-9853

info@mywordsolution.com

Ask Mechanical Engineering Expert

problem 1: A reactor wall 320 mm thick is made up of inner layer of fire brick (k = 0.84 W/mK) covered with a layer of insulation (k = 0.16 W/mK). The reactor operates at a temperature of 1325oC and the ambient temperature of 25o C. Determine (a) thickness of fire brick and insulation which gives minimum heat loss. find out the heat loss presuming that the insulating material has a maximum temperature of 1200o C at the interface.

problem 2: A furnace wall is made up of three layers of thickness 250 mm, 100 mm and 150 mm with thermal conductivities of 1.65 W/moC, k2 and 0.2 W/moC respectively. The inside is exposed to gases at 1250oC, with a convection coefficient of 25 W/m2 oC and inside surface temperature is at 1100oC, the outside surface is exposed to air at 25o C with
convection coefficient of 12 W/m2oC. Determine

i) The unknown thermal conductivity (k2).
ii) The overall heat transfer coefficient. 
iii) All surface temperatures. 
 
problem 3: A steam main 250 mm in diameter and 225 m long is covered with 50 mm of high temperature insulation (k = 0.095 W/mK) and 40 mm of low temperature insulation (k = 0.065 W/mK). The inner and outer surface temperatures are 400oC and 50oC respectively. find out:

i) The total heat loss per hour
ii) The total heat loss per m3 of outer surface
iii) The heat loss per m2 of the pipe surface
iv) The temperature difference between two layers of insulation.

problem 4: A hollow sphere of pure iron contains a liquid chemical mixture which releases 30 kW of energy. The I.D and O.D of the sphere are 15 cm and 30 cm respectively. If the outside temperature of the sphere is 40o C, determine the temperature at a location 2.5 cm away from the outer surface. Assume k = 70 W/m K.

problem 5: An electric current is passed through a composite wall made up of two layers. First layer is steel of 10 cm thickness and second layer is brass of 8 cm thickness. The outer surface temperature of steel and brass are maintained at 120o C and 65oC respectively.

Assuming that the contact between two slab is perfect and the heat generation is 1,65.000 W/m3. Determine (i) Heat flux through the outer surface of brass slab (ii) Interface temperature.

problem 6: A concrete wall of 1 m thick is poured with concrete. The hydration of concrete generates 150 W/m3 of heat. If both the surfaces of the wall are maintained at 35o C, find the maximum temperature in the wall?

problem 7: A copper wire of 40 mm diameter carries 250 A and has a resistance of 0.25x10-4 ? cm/length. Surface temperature of copper wire is 250o C and the ambient air temperature is 10oC. If the thermal conductivity of the copper wire is 175 W/mK, find out:

i) Heat transfer coefficient between wire surface and ambient air.

ii) Maximum temperature in the wire.

problem 8: A sphere of 100 mm diameter having thermal conductivity of 0.18 W/mK. The outer surface temperature is 8o C and 250 W/m2 of energy is released due to heat source. find out the:

i) Heat generated.

ii) Temperature at the centre of the surface.

problem 9: Determine the heat transfer through the plane of length 6m, height 4m and thickness 0.30 m. The temperature of inner and outer surfaces are 100o C and 40o C. Thermal conductivity of wall is 0.55 W/mK. 
 
problem 10: A hollow cylinder 5 cm inner diameter and 10 cm outer diameter has inner surface temperature of 200o C and outer surface temperature of 100oC. Determine heat flow through the cylinder per metre length. Also determine the temperature of the point half way between the inner and outer surfaces. Take k = 1 W/mK.

Mechanical Engineering, Engineering

  • Category:- Mechanical Engineering
  • Reference No.:- M93710
  • Price:- $90

Guranteed 48 Hours Delivery, In Price:- $90

Have any Question? 


Related Questions in Mechanical Engineering

A cubical piece of wood with an edge l in length floats in

A cubical piece of wood with an edge L in length floats in the water. The specific gravity of the wood is 0.90. What moment M is required to hold the cube in the position shown? The right-hand edge of the block is flush ...

Describe the mil-std-1312 nas test name three generic ways

Describe the MIL-STD-1312 (NAS) test? Name three generic ways to prevent or at least minimize self-loosening? Define prevailing torque? A proper length-to-diameter ratio for the bolt can reduce or eliminate self-loosenin ...

The bar shown has a varying cross section and is fixed

The bar shown has a varying cross section and is fixed rigidly at both walls. The crosssectional area of the narrower section is A; the cross-sectional area of the wider section is larger by a factor of m , or m A. Using ...

Write two pages research paper about the air condition

Write two pages research paper about the air condition system in aircraft. Include diagrams or graphs.

A small three-phase ig has the following nameplate data 110

A small three-phase IG has the following nameplate data: 110 V, 1.140 rpm, 60 Hz, Y connection, and 1250 W. The blocked rotor test at 60 Hz yielded the following: I = 69.4 A, P = 4200 W. The turn ratio between stator and ...

A linear spring k is to be designed to stop a 20-mg

a linear spring k is to be designed to stop a 20-mg railroad car traveling at 8km/h within 400 mm after impact. Find the smallest value of k that will produce the desired result.

Name several ways by which the loss of initial preload can

Name several ways by which the loss of initial preload can be reduced ? Roughly how much embedment relaxation could we expect from new parts used in a non-gasketed, steel joint? Define elastic interactions. How can elast ...

The probability of a linear molecule being in a particular

The probability of a linear molecule being in a particular rotational level J depends on the temperature, and for J 7 0 there is a temperature Tmax at which the probability for that level reaches a maximum. Derive an exp ...

A series of calibration tests is conducted on a pressure

A series of calibration tests is conducted on a pressure gage. At a known pressure of 1000 psia it is found that 30 percent of the readings are within 1 psia of the true value. At a known pressure of 500 psia, 40 percent ...

A typical diver inhales 0450 liters of air per breath and

A typical diver inhales 0.450 liters of air per breath and carries a 25 L breathing tank containing air at a pressure of 300. bar. As she dives deeper, the pressure increases by 1 bar for every 10.08 m. How many breaths ...

  • 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