Importance & Requirement of CFD Analysis

Generally CFD analysis is carried out where there is a flow of water or any stream involving sumps, pumps, pipe/channels etc. The fluid flow in sumps is rather complex involving expansions, turns together with fluid structure interaction. It is essential to ensure that pumps operating in such sumps get smooth swirl free flow at its entry. Traditional approach was to carry out sump model studies experimentally with a reduced scale model and applying Froude Similarity rules. 

Computational Fluid Dynamics (CFD) has recently come up as an alternative approach to investigate the complex fluid flow phenomenon in sumps. It is a software based application to study various fluid dynamics. It is rapidly becoming an important tool for analysis and design in hydraulic engineering. Hydraulic engineering encompasses a broad range of activity from flow in a river to design of structures to control and distribute/divert water for various purposes. These flow problems have features that are not commonly found in other applications. 

In the case of pump industry applications, CFD tools are important in view of analysis of the hydraulic passage of the pumps and sumps. For impeller inlet, CFD can help to improve the inlet flow distribution by proper designing/ checking the quality of flow in pump sump. In case of sumps, CFD analysis is used to investigate flow quality entering into the pump at various combinations of pumps in operation. The analysis is done at minimum water level with pumps running at duty point. If the performance of sump is satisfactory at minimum water level, then the performance of the sump will be satisfactory at all other higher water levels because of reduction in velocities.

Questions from Tech Fests on CAD softwares

Problem 1:
To design a concept City Bus that may or may not exist. Innovate the design (e.g. multi-storied bus etc.) such a way that could be celebrated as a real public transport especially for crowded countries like India . The must parts are: Wheels, lights, seats , exhaust and windows & doors.









Problem 2
To design a Concept Car that may or may not exist . Innovate the design that
could bring about improved ergonomy to the user and boost the performance of the vehicle. The must parts are: Wheels, seats, steering, exhaust and windows & doors.

Problem 3
To design a Concept Bike that may or may not exist. Innovate the design to improve the ergonomic of the user as well as the performance of the bike . The must parts are: Wheels, handle, head light(s), fuel tank, seat, exhaust and the suspension system.

Problem 4
To model a pistol. Innovate the design to improve the ergonomy of the user. The must parts are: Trigger, barrel , magazine tube, recoil spring, main spring, slide and frame.

Software problems on mechanical systems for mechanical engineers

Question 1: 
Draw the profile of a cam operating a roller reciprocating follower having a lift of 40mm. The roller diameter is 20mm. The minimum radius of the cam is 30mm. The cam raises the follower with SHM for 110 degree of its rotation followed by a period of dwell for 80 degree. The follower descends for next 120 degree rotation of the cam with uniform acceleration and deceleration followed by a dwell period. Consider, the cam rotates at a uniform speed of 120 rpm.

Question 2:
A piece of chalk is subjected to combined loading consisting of a tensile
load P and torque T .The chalk has an ultimate strength σu as determined in a simple tensile test. The load P remains constant at such a value it produces a tensile stress 0.51 σu on any cross-section. The torque T is increased gradually until fracture occurs on some inclined surface.

Assuming that fracture takes place when the maximum principal stress σ1 reaches the ultimate strength σu, determine the magnitude of the torsional shear stress produced by torque T at fracture and determine the orientation of the fracture surface.

Solve by making a Mohr`s circle either using Matlab OR any other coding C and C++

Question 3:
A common problem with water dispensers is the decreasing flow rates when the water level falls, at times this becomes extremely irritating when flow rates become extremely low. Think about what could be done to eliminate this problem and ensure maximum possible flow rates at all time. Imagine yourself filling a bottle from a dispenser how irritating would it be when the level goes down to the orifice itself and it takes hours filling up a bottle. And eventually you are left with the only choice of tilting the container to increase the flow.

Now let us be logical when could we get a maximum flow rate?????
YOU MAY ASSUME :
A water tank of a cuboidal shape has water filled up to the brim initially. The dimensions of the tank are:
Length = L
Height = H
Width = W
There is an orifice on the side of the tank at a height ‘h’. Water flows out of the orifice and the level of water in the tank starts receding. In order to maintain maximum flow rate of water at all times the tank is tilted about the vertical axis at point A.


Input:
Height of the orifice ‘h’ .
Dimensions of the tank ‘L’, ‘H’, ‘W’ .
Output:
Plot a graph between angle of tilt ‘α’ and time ‘t’ and find the time in which the water would flow out when ensuring maximum flow rates at all times.

Questions from Technical Fests based on CAD (Computer Aided Design) and 3D mechanical softwares

1. Design a 3D train passenger compartment without a roof (in AutoCAD). It should include - body of the compartment having doors and windows, axle and wheels, inside structure having seats, walls and cabin etc. The design should have well defined dimensions close to real life train compartment such as length of
compartment, thickness of walls etc.

Any modification can be made in the design structure but should be reasonable and justified.

2.Design a Concept Car. It need not be a running or working model i.e. the mechanism of working is not considered.The design may include any kind of new concept i.e. the car may or may not be in existence. But the concept should be well justified. The design should include atleast car body having wheels, steering, windows, lights, seats, mirrors. More marks will be awarded for additional and complicated designed parts. The design should be made in either PRO-E, CATIA or SOLIDWORKS.
The dimension details of the designed model and brief description of the new design concept added (if any) is also required.

3.Design a concept bike. It need not be a running or working model i.e. he mechanism of working is not considered. The design may include any kind of new concept i.e. the bike may or may not be in existence. But the concept should be well justified. The design should include atleast bike body including wheels, handle, lights, seat, mirrors, exahust. More marks will be awarded for additional and complicated designed parts. The design should be made in either PRO-E, CATIA or SOLIDWORKS. The dimension details of the designed model and brief description of the new design concept added (if any) is also required.

 

Questions on Mechanical Design Softwares

A) Design a 4 stroke, single cylinder, spark ignition IC engine. Your design should show following features:

1: cylinder

2: piston, piston rings and gudgeon pin

3: connecting rod with small and big end bearing

4: crank, crankshaft and crankpin

5: valve gear mechanism (cam, pushrod, rocker- arm, spring and valves)

Q1. Make a conventional IC engine without simulation.

Q2. Make a conventional IC engine with simulation.

B) Design a revolving chair. Come with your creativity for the improvement of comfort level and appearance. Chair is to be used for office purpose.

C) Make two dimensional motorcycle with the help of Auto-CAD

D)  Design a wheel chair with auto lock facility during free roll (proper brake arrangement to avoid overspeed of the chair in downward slope) in Auto CAD, PRO/E, Solidworks, IDEAS or any other software.

E) Make a conventional bicycle in Auto CAD with auxiliaries like basket, carriage, water bottle holder etc. 

F) Make a Helicopter with an animation - increase in speed of rotation blades lifts the helicopter upward and by decreasing the speed of the rotation blades leading to downward motion in PRO/E or IDEAS.

ProE based questions from Tech Fests

1. Design a DIFFERENTIAL which should include Spiral Bevel Gears, Outer Body, Shafts etc. Final assembly must have all required motion of gears (Mechanisms) .
2. Design a TABLE FAN which should have fan, base support, outer grill etc. The assembly must have running fan with its axial oscillation by using only 1 SERVO MOTOR. Think appropriate mechanism.
3. Design a BICYCLE which should include Suspension system, Gears, Brakes etc.The judgement criteria will be based on the innovation, creativity and feasibility.
4. Design a YACHT which should include Propeller, minimum two Decks and proper Aerodynamic Design etc. The judgement criteria will be based on the innovation, creativity and feasibility.
Source : Avishkar 2010

PROE

Integrated 3D CAD/CAM/CAE Solutions for Any Size Design Challenge. Pro/ENGINEER is the standard in 3D product design, featuring industry-leading productivity tools that promote best practices in design while ensuring compliance with your industry and company standards. Integrated, parametric, 3D CAD/CAM/CAE solutions allow you to design faster than ever, while maximizing innovation and quality to ultimately create exceptional products.

Benefits

* Powerful, parametric design capabilities allow superior product differentiation and manufacturability
* Fully integrated applications allow you to develop everything from concept to manufacturing within one application
* Automatic propagation of design changes to all downstream deliverables allows you to design with confidence
* Complete virtual simulation capabilities enable you to improve product performance and exceed product quality goals
* Automated generation of associative tooling design and manufacturing deliverables

AutoCAD

AutoCAD software lets you design, visualize, and document your ideas clearly and efficiently. With AutoCAD 2009 you’ll move to new highs of productivity. New features help conceptualize and visualize designs, accelerate tasks, and allow commands to be easily found
This is also the product of Autodesk. Latest version released AutoCAD 2009

Autodesk Inventor

Autodesk Inventor software provides a comprehensive set of 3D modeling and mechanical
design tools for producing, validating, and documenting complete digital prototypes. The Inventor model is a 3D digital prototype that helps users visualize, simulate, and analyze how a design will work under real-world conditions before a product or part is ever built—helping manufacturers get to market faster with fewer physical prototypes and more innovative products.

Softwares for different purposes

Computational Fluid Dynamics software's
Fluent

Analysis (FEA based softwares)
Ansys
Nastran
Abaqus
Dytran

Crash Simulation Softwares
Ls Dyna
Mademo

Auto Cad is best suitable for drawing and drafting
CATIA (mainly used in aerospace- famous for its inbuild free form shapes and surfaces)

Modelling
Pro/E (widely used)
Solidworks (next widely used)
Unigraphics
Ideas (more number of features are present in this)
Solid edge

Uni Graphics
Surfacer (Leading software for surface modelling. Now it is in built in UGS NX 5.0)

Anukalpana - a missile trajectory simulation software

FLO Series - software -Pipe Flo, Pump Flo
CAESAR - Pipeline stress Analysis
STAAD - Structural Design
PDS - Planned Design Software
Magma - Solidification Simulation Software

Process Simulation Model Software:
Hysys
Aspen Plus

To view Auto CAD drawing without Auto CAD Software - Bentley View

Structural Design Softwares :
TEDDS
STAAD
STRAP

Water Supply & Drainage System Software:
Sewer CAD
Water CAD
Storm CAD

Design of Flyovers & Signals :
Geo-Comp
Pave Mass
Eagle Point

Desigining - projects

Designing Softwares for Mechanical

Pro/E
Catia
Ideas
Solidworks
Auto Cad
Inventor
Solid Edge

Nastran
Unigraphics
Ultramarine MOSES - Motion Analysis Software
ABAQUS
PV Elite - Design calculations of Pressure Vessels
ANSYS - Analysis based on FEA
CAESAR II - Strees Analysis Software
SACS
PDMS - 3D Modelling
NX NASTRAN
FEMAP