%0 Journal Article 
%A Banegas Carrillo, Isabel Pilar
%T Influence of constructive materials, geometry and other variables on heat flow and output power of an air-cooled GTAW torch
%D 2008
%U http://hdl.handle.net/10317/145
%X Most kinds of GTAW machines that are available in market are large,
solid, expensive and with voluminous power sources. These great machines are
water-cooled GTAW machines that require input power and water connections
beside the electrical connections, making them heavier and less portable than
other welding machines.
It could be easily stated that the water-cooled machines´ disadvantages are
advantages for air-cooled GTAW. Several producers, like racecar, street or
building constructors, would prefer the features of air-cooled welder machines
because they are smaller, lighter, and easy to move, less complexity with fewer
expensive internal components and less maintenance.
However, air-cooled GTAW has a disadvantage that water-cooled GTAW do not
have, and it is that its amperage range is much shorter. That is, these machines
cannot work with high current or over long times because the torch elements
and internal electrical components tent to overheated. Mostly, all air-cooled
GTAW that you can find in industrial market have a 200-250 amperes maximum
output current. This is the project starting-point; how can we achieve a higher
output current of air-cooled GTAW?
This project intends to answer to this question. It analyzes the physically
behaviour of this torch and tries to improve air-cooled GTAW output power
through increasing their cooling capacity. These are the processing steps:
1. Design new model
Four prototypes with different geometries were designed and built for
making the experiments in the lab. At the same time, four finite element models
(FEM) analogous to the real construction were constructed for simulation in
Ansys by: (1) creating the geometry, defining material and properties; (2)
Defining element type and meshing; (3) Applying the adequate boundary
conditions and loads that make the simulations behave as close to physicality
as possible.
2. Validation
Once all models were built, the prototypes were assembled in the lab and
finite element models were ready to simulate, the next step was to validate. In
the workshop some experiments were performed with the same experimental
conditions for FEM models that were simulated in Ansys. The results of FEM
are compared with experimental results to know if its behaviour is similar
enough to the prototypes.
3. Variables in heat transfer
After comparing Ansys models with the prototype, some variables that
might have an influence on heat transfer were simulated to know how the heat
transfer in welding torch behaves physically.
4. Conclusion
In this last step, a short summary of the results and a discussion of
the air-cooled GTAW’s weakness and strengths are made. Also, some
possible suggestions for the initial problem are described.
%K Ingeniería Eléctrica
%K Soldadura
%~ GOEDOC, SUB GOETTINGEN