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Computational modelling of a smart impeller actuated by shape memory alloys
Author(s)
Fuhnwi, Godwin Fonguh
Date Issued
2011
Type
Thesis
Publisher
Cape Peninsula University of Technology
Abstract
Smart (SMA-Shape Memory Alloy) Technology continues to advance rapidly
as engineers move closer to and understand better the industrial and
commercial needs for SMA. As a matter of fact, all types of products, which
exercise some type of control over their function, are rapidly making their way
into the marketplace [36] Nonetheless, nowhere has been evidence in the
development of a SMA impeller.
Unlike traditional impellers with no control over their function and sometimes
fixed angle of attack, this paper demonstrates numerical investigations using
analytical algorithms (Matrix laboratory programming and excel spread sheet)
and advanced computer simulation package, Engineering Fluid dynamics
(EFD) into the feasibility of using a smart impeller to study the performance of
a pumping system and the best angle of attack for a Shape Memory Impeller.
Primarily, Bench mark data and dimensions are obtained from a standard
centrifugal pump run on a FM21 demonstration unit. Using the same standard
centrifugal pump, and keeping all other dimensions the same but altering the
angle of attack, EFD simulations where made.
From analytical algorithm and EFD comparison, it was evident that the best
angle of attack is 12 degree at the outlet angle with respect to the inlet angle.
From EFD results, it is palpable that, by increasing the angle of attack from 35
degree to 45 degree at the outlet there will be huge increase in flow rate by
63.47%
There is also a slight decrease in the impeller Torque from 35 degrees to 42
degrees by 0.72%.
It is economically feasible to work at an outlet angle of 42 degrees due to
increase in efficiency of 62.1% and a drop in torque of 0.72% by varying the
outlet angle from 35 degrees to 42 degree.
Understanding how critical actuator design is, it should be suggested that any
shape memory impeller should never be used in critical components without a
prior history of thermal and mechanical loading.
Therefore, a NiTi impeller constitutive model can be designed, with impeller
blades made from NiTi plates, trained to remember its best angle of attack
(Martensitic phase). NiTi shape memory metal alloy (plates-blades) can exist
in a two different temperature-dependent crystal structures (phases) called
martensite [9](lower temperature-normal pumping condition) and austenite [9]
(higher temperature or parent phase-trained best angle of attack.)
as engineers move closer to and understand better the industrial and
commercial needs for SMA. As a matter of fact, all types of products, which
exercise some type of control over their function, are rapidly making their way
into the marketplace [36] Nonetheless, nowhere has been evidence in the
development of a SMA impeller.
Unlike traditional impellers with no control over their function and sometimes
fixed angle of attack, this paper demonstrates numerical investigations using
analytical algorithms (Matrix laboratory programming and excel spread sheet)
and advanced computer simulation package, Engineering Fluid dynamics
(EFD) into the feasibility of using a smart impeller to study the performance of
a pumping system and the best angle of attack for a Shape Memory Impeller.
Primarily, Bench mark data and dimensions are obtained from a standard
centrifugal pump run on a FM21 demonstration unit. Using the same standard
centrifugal pump, and keeping all other dimensions the same but altering the
angle of attack, EFD simulations where made.
From analytical algorithm and EFD comparison, it was evident that the best
angle of attack is 12 degree at the outlet angle with respect to the inlet angle.
From EFD results, it is palpable that, by increasing the angle of attack from 35
degree to 45 degree at the outlet there will be huge increase in flow rate by
63.47%
There is also a slight decrease in the impeller Torque from 35 degrees to 42
degrees by 0.72%.
It is economically feasible to work at an outlet angle of 42 degrees due to
increase in efficiency of 62.1% and a drop in torque of 0.72% by varying the
outlet angle from 35 degrees to 42 degree.
Understanding how critical actuator design is, it should be suggested that any
shape memory impeller should never be used in critical components without a
prior history of thermal and mechanical loading.
Therefore, a NiTi impeller constitutive model can be designed, with impeller
blades made from NiTi plates, trained to remember its best angle of attack
(Martensitic phase). NiTi shape memory metal alloy (plates-blades) can exist
in a two different temperature-dependent crystal structures (phases) called
martensite [9](lower temperature-normal pumping condition) and austenite [9]
(higher temperature or parent phase-trained best angle of attack.)
Additional information
Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2011
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