Mechanical Engineering Answers

Natural gas combustion is being used for steam generation and 5% excess air is incorporated into the combustion. Estimate the composition of the flue gas and compute the % thermal energy loss if the flue gas temperature is 20°C.

A pudding mix is being formulated to achieve a total solids content of 20% in the final product. The initial product has a temperature of 60°C and is preheated at 90°C by direct steam injection using saturated steam at 105°C. If there is no additional gain or loss of moisture from the product, what is the total solid content of the initial product?

Steam with 80% quality is being used to heat a 40% total solids tomato puree as it flows through a steam injection heater at a rate of 400 kg/hr. The steam is generated at 169.06 kPa and is flowing to the heater at a rate of 50 kg/hr. Assume that the heat exchanger efficiency is 80%. If the specific heat of the product is 3.2 kJ/kg. K, determine the temperature of the product leaving the heater when the initial temperature is 50°C. Determine the total solids content of the product after heating. Assume the specific heat of the puree is not influenced by the heating process.

manufacturing is a basic subject which related to basic need of people as well as standard of a country discuss why it is necessary for all engineers to know about manufactruing processes

Lubricating oil enters the tubes of a heat exchanger at 74C and leaves at 34 C. The diameter of the tube is 50 mm and the oil flow through the tube at 2.5 m/s.
Input power to the system is 30 kW.
The specific heat capacity of the oil is 2.28 kJ/kgK and the density is 900 kg/m3. Determine;
a. The mass flow rate of the oil.
b. The thermal efficiency of this heat transfer process.

For a reversed heat engine the evaporator and condenser temperature at -5 and 50 degree Celsius respectively. The specific heat capacity at constant pressure is 0.956kJ/KgK if the mass flow rate of the refrigerant is 0.012kg determine the evaporator heat loads, C.O.P Of the refrigerator and heat pump and power

The thermal resistance of the pipe wall can be ignored due to the pipe's relatively low wall thickness. Based on the below worked example we can see accounting for the mean pipe wall thickness the difference between the above and below answer's is 2.60pc.

If the wall thickness was to increase it would be prudent to use the logarithmic expression as this accounts for the change in area which becomes more important the thicker the pipe wall.

However, as no dimensions have been provided for the pipe wall thickness we can assume that the pipe wall is this and thus have a negligible effect impact.

Determining the width of the plate:

W=2πr_(mean )

A compressed air storage cylinder has a volume of 1 m3 and contains air at an absolute pressure of 2 MPa and temperature 25°C. A quantity of the air is released during which the temperature of the remaining air falls to 15°C and the pressure to 1 MPa. The characteristic gas constant for air is 287 Jkg−1K−1.

Calculate the mass of the air released.

A pile driver hammer of mass 272 kg falls freely through a distance of 4.2 m to strike a pile of mass 516 kg and drives it 75 mm into the ground. The hammer does not rebound when driving the pile. Determine the average resistance of the ground. (Use D’Alembert’s principle and compare the principle of Conservation of Energy when solving the problem).

Task 1: A pile driver hammer of mass 272 kg falls freely through a distance of 4.2 m to strike a pile of mass 516 kg and drives it 75 mm into the ground. The hammer does not rebound when driving the pile. Determine the average resistance of the ground. (Compare, use and contrast the use of D’Alembert’s principle with the principle of Conservation of
Energy when solving the problem given in Task 1. You must fully answer each task and show all steps, including text. You must include labelled diagrams to aid your solutions).