# 热力学和流体力学代考代写Thermodynamics,Fluid Mechanics

MCEN机械工程系课程Thermodynamics and Fluid Mechanics代写物理代写中的热力学也经常有代考接单，此次是六成流体力学内容，四成热力学内容，由两个写手共同完成，3小时考试热力学与流体力学代考过程非常完美！

Part I – Thermodynamics Question 4 (10 marks)
Consider an ideal Otto cycle, with a compression ratio of 11. At bottom dead centre before
the compression, the air is at 100 kPa, 300 K. The temperature at the end of the isentropic
expansion process is 700 K. Assume constant specific heats at room temperature, and the
following properties of air:
Cv = 0.718 kJ/kg.K, Cp = 1.005 kg/kg.K, R= 0.287 kJ/kg.K and γ = 1.4.
(a) Show and label the cycle on a P-v diagram, labelling all states, work and heat
transfer processes. (4 marks)
(b) Find the temperature and pressure at the beginning of the constant volume heat
(c) Find the temperature and pressure at the beginning of the isentropic expansion
process. (2 marks)
(d) Determine the efficiency of the cycle. (2 marks)

Part II – Fluid Mechanics Question 3：

A cylindrical vessel is partially filled with water, and starting from rest the vessel is
rotated at a constant angular velocity 𝜔. The velocity 𝑉􀰏 within the fluid depends on
radial location 𝑟, the time from the start of rotation 𝜏, 𝜔 and the fluid properties.
(i) Find the non-dimensional groups that relate 𝑉􀰏 and the other parameters of
relevance. (8 marks)
(ii) If, in another experiment, honey is rotated in the same vessel at the same angular
speed, determine from your dimensionless parameters the ratio of the time for the honey and
water to attain the steady motion. Assume water and honey to be of the same density and
honey to be 2000 times more viscous than water. (4 marks)
(iii) At steady state, determine and explain briefly which non-dimensional groups will
be irrelevant. Then, from the remaining relevant group/s determine how 𝑉􀰏 will vary with 𝑟.
(4 marks)