Let us worry about your assignment instead!

We Helped With This Engineering Homework: Have A Similar One?

SOLVED
CategoryEngineering
SubjectOther
DifficultyUndergraduate
StatusSolved
More InfoComputer Engineering Homework Help Online
17191

Short Assignment Requirements

I just want the coding for all the parts included in the attachement below

Assignment Description

ENCH298: Assignment 2

Can Cooling Dynamics

 

Due:  9 am, Monday 22 May 2017 at the lab, or in a Level 5 assignment box.

 

This homework is worth up to 10% of your final grade in ENCH298.

 

You may complete this assignment in pairs, but you must work with a different person from the last ENCH298 assignment.

 

Complete the tasks listed below and write a brief report of the results.

Overview

It is a warm summer day (24°C) day and you feel like a cold drink.

 

You have a can of drink that has been sitting on the kitchen bench in the sun and has warmed up to 20 °C. Unfortunately, your fridge has broken down and will take days to get fixed.  But you are able to get some uniformly sized, 25 mm diameter, spherical ice balls and you have a 9 L plastic bucket.  You intend to add enough ice balls to a bucket of water initially at 15 °C and immediately add the can of drink.  As soon as the ice has melted you remove the can to drink it.

 

Use your engineering modelling and simulation skills to determine how much ice and water to add to reduce the drink temperature to 8 °C once all the ice has melted.  At all stages in the modelling and simulation consider the practical validity of your model.

 

An important part of this assignment is the physical interpretation of parameters and results.  Mathematical solutions in isolation will not be sufficient. 

 

A model is given below.

 

Objective

To determine the temperature of drink inside a can over time after being added to a bucket containing water and ice balls.

 

Diagram and Scope

The bucket and contents as shown in the figure

 

 

 

 

 

 

 

 

 

 

Assumptions

Uniform temperature within the water.

Uniform temperature within the ice, i.e., there is negligible conduction resistance within it.

Uniform temperature within the can.

Constant and uniform ambient conditions.

Constant and uniform specific heat capacities and densities.

The ice is fully submerged (not true).

The can is fully submerged.

The ice is initially 0 °C.

The ice is spherical and all balls melt equally so are the same size at any time. The thermal mass of the bucket wall and can wall are negligible.

No evaporation.

There is heat gain from the ambient air into the bucket through the walls and top. The heat transfer coefficients are constant.

 

Equations

The required balances are:

            The mass of ice

            The mass of water

            The energy of the water

            The energy of the drink

 

Because we assume that the ice is always at 0 °C and we have a balance for the mass of ice, then the energy of the ice can be calculated, so an ice energy balance is not required. 

 

Balance

Mass of ice

Total mass of liquid water

     𝑑𝑡                𝑚𝑒𝑙𝑡𝑖𝑛𝑔

 

 

𝑑𝑚𝑤𝑎𝑡𝑒𝑟

(2)  

                                                       𝑑𝑚𝑖𝑐𝑒 = −𝑚̇                                                              (1)  

 =𝑚̇ 𝑚𝑒𝑙𝑡𝑖𝑛𝑔 𝑑𝑡

Energy of liquid water

                                                  𝑑𝐸

                                                                 𝑤𝑎𝑡𝑒𝑟 =𝑄𝑎𝑚𝑏 −𝑄𝑖𝑐𝑒 −𝑄𝑐𝑎𝑛                                             (3)  

𝑑𝑡

Energy of drink in the can

                                                                𝑑𝐸

                                                                                   𝑐𝑎𝑛 = 𝑄𝑐𝑎𝑛                                                           (4)  

𝑑𝑡

Algebraic equations

                                                              𝑚𝑖𝑐𝑒 =𝑁𝜌𝑖𝑐𝑒 𝜋𝐷3                                                          (5)  

6

                                                                                   𝑄𝑖𝑐𝑒                                                                                                                     (6)  

                                                                                 𝑚𝑒𝑙𝑡𝑖𝑛𝑔                                        

Δ𝐻𝑓𝑢𝑠𝑖𝑜𝑛

 

                                           𝐸𝑤𝑎𝑡𝑒𝑟 = 𝑚𝑤𝑎𝑡𝑒𝑟𝐶𝑝,𝑤𝑎𝑡𝑒𝑟(𝑇𝑤𝑎𝑡𝑒𝑟 −𝑇𝑟𝑒𝑓)

(7)  

                                                𝐸𝑐𝑎𝑛 = 𝑚𝑐𝑎𝑛𝐶𝑝,𝑑𝑟𝑖𝑛𝑘(𝑇𝑐𝑎𝑛 −𝑇𝑟𝑒𝑓)

(8)  

                                                   𝑄𝑖𝑐𝑒 = 𝑈𝑖𝑐𝑒𝐴𝑖𝑐𝑒(𝑇𝑤𝑎𝑡𝑒𝑟 −𝑇𝑖𝑐𝑒)

(9)  

                                                  𝑄𝑐𝑎𝑛 =𝑈𝑐𝑎𝑛𝐴𝑐𝑎𝑛(𝑇𝑤𝑎𝑡𝑒𝑟 −𝑇𝑐𝑎𝑛)

(10)

                                                𝑄𝑎𝑚𝑏 =𝑈𝑎𝑚𝑏𝐴𝑎𝑚𝑏(𝑇𝑎𝑚𝑏 −𝑇𝑤𝑎𝑡𝑒𝑟)

(11)

                                                                𝐴𝑖𝑐𝑒 =𝑁𝜋𝐷2

(12)

                                                                              𝑚̇             =

 

Variables

Independent

            t                time                                                                              s

 

Dependent

            mice              Mass of ice in the bucket                                             kg

            mwater          Mass of water in the bucket                                         kg

            Ecan           Energy of the drink in the can                                     J

            Ewater        Energy of the water                                                     J

               m& melting     Mass flow rate from the ice due to melting                 kg/s

           

            Qice              Flow rate of heat into the ice                                       J/s

            Qamb         Flow rate of heat into water from ambient air             J/s

            Qcan             Flow rate of heat into the can from the water              J/s

            Twater           Water temperature                                                       °C

            Tcan              Temperature of the drink in the can                            °C

            D              Diameter of the ice spheres                                         m

            Aice           Surface area of the ice                                                 m2

 

Parameters

            Uice           Overall heat transfer coefficient from water to ice      W m-2 K-1

            Uamb         Overall heat transfer coefficient for air to the bucket W m-2 K-1

            Ucan          Overall heat transfer coefficient for the can to water W m-2 K-1

            N                   Number of ice spheres

            mcan             Mass of drink in the can                                              kg

            Cp,water        Specific heat capacity of water                                   J kg-1K-1

            Cp,drink        Specific heat capacity of the drink                              J kg-1K-1

            Tamb          Ambient air temperature                                              °C

            Tref               Reference temperature                                                 0 °C

            Hfusion       Latent heat of fusion (positive)                                   J kg-1

 

Initial Conditions

IC’s are required for    mice(t0) or N and D(t0)

            mwater(t0

            Ewater(t0) or Twater(t0)

            Ecan(t0) or Tcan(t0)

 

Tasks

These tasks require Matlab simulation and engineering thinking.  Think about the answers you obtain.

a)      Manipulate the model to replace energy with temperature and get a set of 4 differential equations with the additional algebraic equations that can be used to evaluate terms in the differential equations.

b)      Write a prediction for the responses of the four differential variables based only on your intuition. (In other words, think about the likely response before you simulate it to help with verification.)

c)      Simulate, using your 2nd order RK (also known as Heun’s method or modified Euler’s method) code and Matlab ode23.  You should be able to write the equations in a Matlab function that is identical for your 2nd order RK and ode23. For this simulation you can choose any unknown parameter values.

d)      Adjust the initial mass of water and the mass of ice (i.e., the number of ice balls) to achieve the desired temperature of 8 °C in the can. This can be done by trial and error but you should explain the strategy you use.

e)      What practical combination of water and ice mass gives the fastest cooling?

f)       Check the influence of step size on your RK2 method and of tolerances in ode23 on the answers to d).  For ode23 you can use the syntax:

options=odeset('RelTol', 1e-6, 'AbsTol', 1e-6);

[t x]=ode23(@Equations, tspan, x0, options);

 

The error tolerance used by ode23 is then max(AbsTol, RelTol × x

 

Once the ice has melted, some of the variables become zero, but continued simulation should be possible.

g)      Check your simulation results to see what solution you get when the mass of ice reduces to zero. Comment on this and seek to improve the results if necessary and possible.

 

Many assumptions were made in the modelling process. 

h)      Evaluate the influence of any parameters that you are unsure about.  (As a counterexample, there is no need to check the influence of the specific heat capacity of water.)

i)       You might be able to carry out simple experiments, and use the results with your Matlab simulation, to get a better estimate of the heat transfer coefficient for ice in water.

j)       Do you think it is worthwhile insulating the bucket? (Justify your answer).

k)      What is the maximum number of cans (with the same number of each type) that you can cool down to 10 °C in the bucket?

 

Report

For this project a report should include

             

      Title page.

      Table of Contents.

      Short introduction to the problem.

      A clear model with a statement of the modelling objective, a diagram of your system (bucket, ice, can).

      Answers for each part with an outline of the part with as much supporting data, graphs, comments, etc. as suitable.

      Appendices clearly showing selected m-files that were used for each of the parts.  You do not need to include complete listings showing all the different code used.  Just include one complete m-file and then parts that are changed for other parts.

The main part of the report should contain sufficient information to enable an engineer to understand what you have done, and interpret your answers.  Appendices should be used for the detail for someone who wants to reproduce your work.  Refer to appendices from the main part of the report.  

 

There is no page limit but if you are approaching 10 pages for the main parts, think about making it more concise.  Bored markers tend to give lower marks.

Customer Feedback

"Thanks for explanations after the assignment was already completed... Emily is such a nice tutor! "

Order #13073

Find Us On

soc fb soc insta


Paypal supported