project question:

'Design and build a thrust measurement system for model aircraft engines '

1- Questions

i) sketch

ii) ideas

iii) plan

iv) introduction, background, theory , abstract etc...

2 kilogram of R-134a fills a 0.14-m3 weighted piston–cylinder device at a temperature of –26.4°C. The container is now heated until the temperature is 100°C. Determine the final volume of the R-134a.

Hot water from a boiler of power plant are discharged through a 0.2-m-diameter, thin-walled pipe with a velocity of 3.5 m/s. The pipe passes through a room whose air temperature is 3°C and the exterior surface of the pipe is uninsulated and pipe length is 30 m.  

(a) At a position in the pipe where the mean water temperature is 40°C, determine the heat loss and the pipe wall temperature.

(b) If the pipe is covered with a 20-mm-thick layer of insulation (k = 0.5 W/m K) what are the pipe wall temperature, the outer surface temperature, and the heat loss?

Explain the difference between the principle of impulse & momentum approach and the conservation of impulse & momentum approach.

Develop and explain each step the general equation of heat transfer by conduction in a constructive way starting from an element general differential in the cartesian coordinate system and then reduce to get:
1) Laplace's equation (in R3)
Δ? = 0
2) The Poisson equation (with constant thermal conductivity ?)
Δ? + ? '''= 0

Δ is the Laplacian operator and ? ''' is a source term.

Note: start the analysis from a differential element with volume ??????. Make a energy balance over this volume considering that it can increase if temperature in time according to its thermal capacity. Give more generality to the model assuming there is a source term ? ''' which can be a source that produces thermal energy or consume it.

Fully developed (both hydrodynamic and thermal) laminar flow is pushed through a thin-walled circular pipe of diameter 13 mm. The fluid flows through the pipe at a velocity of 0.1 m/sec, has a density of 1000 kg/m^3, a dynamic viscosity of 855 x 10^-6 Pa-sec, a specific heat of 4000 J/kg-K, a Prandtl number of 8, and a thermal conductivity of 0.613 W/(m-K).

The outside of the pipe is subjected to uniform cross flow where the free-stream velocity is 5 m/sec, the density is 1 kg/m^3, the dynamic viscosity is 180 x 10^-7 Pa-sec, the Prandtl number is 0.7, the specific heat is 1000 J/(kg-K), and the thermal conductivity is 0.02 W/(m-K).

The pipe (remember the flow is fully developed everywhere) is 10 m long and is wrapped with a thin heater that is generating uniform flux around the periphery of the pipe.

A) What is the specific thermal resistance (K-m^2/W) at a point 5 m into the pipe from the interior surface of the wall to the mean fluid temperature?

B) Using the conditions outlined above for the isoflux pipe in cross-flow, what is the specific thermal resistance (K-m^2/W) from the outside surface of the pipe (or thin heater surface if you want to think of it like that) to the free stream cross-flow fluid?

As a lubricant engineer, you design a new friction modifier as an additive for synthetic oil to reduce friction between two surfaces. Describe the content of your new friction modifier and mechanism to protect the surface.

For the stress data given below with the nearest error of 1:

27-17-11-24-36-13-29-22-18

23-30-12-46-17-32-48-11-18

18-32-26-24-38-24-15-13-13

18-21-27-20-16-15-37-19-19

a) Construct a frequency distribution table.

b) Construct the three types of statistical graphs.

c) Determine the (1) Mean, (2) Median, (3) Mode, (4) Range,

Variance, and (6) Standard Deviation.

Ai inventor proposes a four -stroke cycle running on helium. The engine has a compression ratio of 8 and maximum operating temperature of 1,500 K. The atmospheric conditions are temperature of 300 K and pressure of 100 kPa. The processes can be approximated as below:

1- 2 isentropic compression

2- 3 constant volume heat addition

3- 4 isentropic expansion

4- 1 constant pressure heat removal

a.

Plot P-v and T-s diagrams for this cycle.

b.

Determine state conditions at the end of each step by filling up the table below.

c. Heat addition

d. Net work

e. Thermal efficiency

Hint: Cp= 5.193 kJ/kg.K, Cv = 3.116 kJ/kg.K, R = 2.077 kJ/kg.K, k = 1.667

Please show work for all questions a-e. Thank You

Course Title: BUSINESS DYNAMICS: SYSTEM THINKING AND MODELLING FOR A COMPLEX WORLD  

                                Required

What System Dynamics

Meaning of feedback, types, with examples

Please Do it Clearly with each step and FAST

Use music wire to make a series of springs with wire diameters [0.075”, 0.080”, 0.085”, 0.090”].
Each spring should have a free length of 3” and rate of 50 lbf/ft and exactly 20 total coils. The
ends are squared and ground and the load factor of safety should be 1.1.
For each wire size, list the figure of merit and the spring index, C.
All else being equal, which wire diameter makes the most meritorious design?

Flue gases from an incinerator are released to atmosphere using a stack that is 0.62 m in diameter and 10.0 m high. The outer surface of the stack is at 45°C and the surrounding air is at 10°C. Determine the rate of heat transfer from the stack, assuming a. there is no wind and, b. the stack is exposed to 21 km/h winds.

1 A steel helical spring carries a compressive load of 32.4 pounds at a deflection of 0.25 inches. Maximum stress is 73240psi. The spring has 1.5 end turns. Calculate the value of c for the spring of minimum volume material. Calculate the value of d and choose the nearest standard wire diameter for the actual spring. Calculate the corresponding R and the number of active coils N_c. Also, calculate the material in the spring.

An ideal refrigeration cycle utilizes R-134a as a working fluid. If the fluid enters the compressor as saturated vapor at 6 C and enters a throttling valve as a saturated liquid at 1.2MPa. Assuming the mass flow rate of fluid is 1 kg/sec. 1. The heat received by the fluid (kJ) is 2. The heat received by the surroundings (kJ) is 3. The power input to the compressor (kJ) is 4. The coefficient of performance is