Engineering Answers

A hot fluid at 200 °c enters a heat exchanger at a mass flow rate of 10000kg/hr. It's specific heat is 2000j/kg°c. It is to be cooled by another fluid enters at 25°c with a mass flow rate 2500kg/hr and specific heat is 400 j/kg°c. The overall heat transfer coefficient based on outside area of 25m^2 is 250W/m^2°c. Find the exit temperature of the hot fluid when the fluid are in parallel flow and counter flow

A machine component is subjected to fluctuating stress that varies from 40 to 100 N/mm². The corrected endurance limit stress for the machine component is 270 N/mm². The ultimate tensile strength and yield strength of the material are 600 and 450 N/mm² respectively. Find the factor of safety using

(i) Gerber theory

(ii) Soderberg line

(iii) Goodman line

Also, find the factor of safety against static failure.

Construct the cumulative distribution function of problem b

An ideal Otto cycle has a compression ratio of 9. Using constant specific heats at room  temperature, determine the thermal efficiency of this cycle and the rate of heat input if the  cycle is to produce 60 kW of power

A solution of washed raw cane sugar is coloured by the presence of impurities. It is to be decolourised by the treatment with an adsorptive carbon in a contact filtration plant. The data for an equilibrium isotherm is given below. The original solution has a colour concentration of 9.6 measured on an arbitrary scale and it is desired to reduce colour to 10% of its original value

Kg carbon/kg solution:

0.001

0.004

0.008

0.02

0.04

Colour units /kg solution

9.6

8.6

6.3

4.3

1.7

0.7

Convert the data to a suitable form for plotting the equilibrium isotherm and determine the quantity of fresh carbon required per 1000 kg of solution for a two stage counter-current operation?

Explain briefly with step by step process?

1.)A 20lbm object is located 300 ft above the ground. What is the potential energy of the object in lbf-ft, BTU, and cal?

2.)A mole of a certain ideal gas was inside a container. The gas has a temperature of 70°F and a pressure of 20 psi. Find the volume of the gas in m^3.

An inventor claims to have developed a heat

engine that receives 700 kJ of heat from a source

at 500 K and produces 300 kJ of net work while

rejecting the waste heat to a sink at 290 K. Is this

a reasonable claim? Why?

Find the values of Cp and ᵞ for a gas whose gas

constant is 0.324 kJ/kg K and Cv = 0 84 kJ/kg K.

If 2.25 kg of this gas with an initial volume of

1.15 m3 undergoes a process during which its

pressure remains constant at 7 bar and its

temperature becomes 280‘C at the end of the

process, calculate: (a) the change in internal

energy, (b) the change in enthalpy, (c) the

transferred heat, and (d) the work done.

A synthetic belt of density 994kg/m³ is used in an open-belt drive. The belt is wrapped around a pulley of diameter 900mm running at 324rpm. If the angle of contact with the small pulley is 2∙π/3 radians and the maximum stress on the tight side is limited to 2000kPa. The coefficient of friction between the belt and the pulley is 0.35 and the belt width and thickness are 250mm and 10mm, respectively.  . Calculate:

 The power transmitted by the belt in Watts (W)

An R-410a heat pump cycle shown in the figure below has an R-410a flow rate of 0.05 kg/s with 5 kW into the compressor. The following data are given:

State 1 2 3 4 5 6

P, kPa 3100 3050 3000 420 400 390

T, oC 120 110 45 -10 -5

h, kJ/kg 377 367 134 280 284

Calculate the heat transfer

a) from the compressor

b) from the R-410a in the condenser

c) to the R-410a in the evaporator