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Please Follow the instructions given in the assignment and please write the work in a report format. Heat Transfer Assignment This assignment consists of 2 different elements. In the first part, you...

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Please Follow the instructions given in the assignment and please write the work in a report format.
Heat Transfer Assignment This assignment consists of 2 different elements. In the first part, you need to select or design a heat exchanger for a waste heat recovery system in cars. The second part is a reflective journal about the unit, a bit similar to the SETU questionnaire but mandatory to capture the thoughts of all students. The assignment needs to be submitted through CloudDeakin as an MS Word or pdf file. Part 1 – Heat Exchanger selection/design Imagine you are part of a product development team that is developing a novel waste heat recovery system to make cars more efficient. One feature of the system is to transfers wasted exhaust heat to the engine oil via a heat exchanger to reduce the friction of the oil, particularly during warm-up, but also during steady-state operation at engine loads below wide open throttle. Your task is to either design or select and source an existing heat exchanger that will be suitable for this application. Even though most driving patterns in a car are highly dynamic you are given most operating conditions as average over the legal fuel consumption drive cycle. In the assignment you need to justify the decisions based on you engineering judgement and by applying the concepts you learned in the heat transfer unit. The priorities for the new product are as follows: 1. Safe operation under all possible operating conditions at ambient temperatures between - 30 °C and +50 °C 2. Maximum efficiency of the heat exchanger to be able to realise the highest possible fuel economy improvement 3. Durability of 150,000km (legal requirement for emission relevant components) 4. Low weight to minimise the negative impact of additional weight towards fuel economy 5. Small external volume to make it easy to package it in the packed and tight engine compartment 6. Low cost 7. Low external temperatures to avoid deterioration, aging or long term damage of nearby plastic components 8. Long term resistance against fouling Page 2 of 3 Operating conditions The following operating conditions should be considered in your selection or design process: ? The test condition is the New European Drive Cycle (NEDC), the duration is 1180 sec ? The exhaust gas consists of corrosive combustion products. The average water content is about 10% ? The average exhaust temperature into the heat exchanger is 434 °C during the NEDC ? The maximum exhaust gas temperature is 625 °C during the NEDC ? The ambient air temperature is 24 °C during the NEDC, this doesn’t change over the test cycle ? The start temperature of all engine components inclusive the exhaust gas heat exchanger and the engine oil is also 24 °C ? The average flow rate of the exhaust gas is 6.9 g/s ? The average oil flow rate is 10 l/min ? The average oil temperature is 60 °C ? The average vehicle speed is 35km/h, the wind speed is simulated proportionally to the vehicle speed by a vehicle cooling fan ? The average exhaust heat flow during the NEDC is 4kW ? The target exhaust gas temperature after the heat exchanger is to be below 90 °C during most parts of the NEDC to be able to utilise the condensation enthalpy of the water as much as possible Deliverables The following deliverables are required as the outcome of your development work, independent if you selected an existing heat exchanger or if you designed your own. If some numerical values that might be required for your calculations are not given in the assignment, you need to estimate them and you need to justify these estimations. Whenever you make assumptions you need to clearly articulate the assumptions, cite the source of your assumptions and add a comment about the potential effect of the uncertainty of your assumptions. ? Material specification that will be used and material thickness ? Average efficiency or effectiveness ? Overall weight ? Outside dimensions ? Package volume ? Maximum average outside surface temperature during NEDC ? Maximum average inside surface temperature during NEDC ? Oil volume in the heat exchanger ? Heat required to warm up the heat exchanger (a lump sum analysis is sufficient) ? Average heat rejected to the ambient ? Effective heat transfer surface ? Layout with definition of inlet and outlet for oil and exhaust Page 3 of 3 ? Sketch of the cross section ? Cost (single unit prototype and if mass produced at 100,000 units per year)
Answered Same Day Dec 22, 2021

Solution

David answered on Dec 22 2021
133 Votes
Heat Exchanger Design
Principles and parameters

We have designed a novel waste heat recovery system to make cars more efficient. It transfers
wasted exhaust heat to the engine oil via a heat exchanger to reduce the friction of the oil, particularly
during warm up, but also during steady state operation at engine loads below wide open throttle. The
design is based on Oil gas Heat exchanger. Oxygen gas having 0.919kJ/Kg.K specific heat capacity and
Fuel oil 1.67 kJ/kg.K
Given Operating Conditions
Cycle Period : 1180sec
Water content of the Exhaust Gases : 10%
Average Exhaust Temperature : 4340C (Outlet)
Maximum exhaust Gas temperature = 6250C
The ambient air temperature is 24 °C during the NEDC, this doesn’t change over the test cycle
The start temperature of all engine components inclusive the exhaust gas heat exchanger and the
engine oil is also 24 °C
The average flow rate of the exhaust gas is 6.9 g/s
The average oil flow rate is 10 l/min
The average oil temperature is 60 °C
The average vehicle speed is 35km/h, the wind speed is simulated proportionally to the vehicle speed by
a vehicle cooling fan
The average exhaust heat flow during the NEDC is 4kW
The target exhaust gas temperature after the heat exchanger is to be below 90 °C during most parts of
the NEDC to be able to utilize the condensation enthalpy of the water as much as possible
Material Specification -----------------------------------------------------------
 Highly Conducting Coppers for making Heat exchanging pipes
 Brasses Alloys are used to provide High resistivity for effective heat generation
 Wrought Martensitic Stainless Steel this is chosen only because of its non co
osive behavior
otherwise it is heavier than Copper not a good option to use in cars but in cases its necessary.
 Aluminum...
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