The heat sink is defined in a set up window with several tabs. Which
of these that are visible or active depends on the problem definition.
The set up tab handles this functionality. There is also an
image that symbolically shows the options selected
The program performs calculations for a range of values of
a step parameter which could be either of:
the pitch, the fin count, the velocity or
the fan speed.
The result is presented in a list that has as many rows as
defined by the count variable. It can be presented in
a large selection of pre-defined diagrams. The entire list can
also be copied to the clip board.
Can be either given temperature difference or given heat
Defines if the fin thickness takes the given value or
if it optimized for each calculation step.
Defines if heat transfer by radiation should be considered
Defines how the air flow is calculated. The fan option is
associated with a fan curve. The velocity and pressure drop options
are associated with single value inputs.
Defines if the bottom plate is isothermal or if there are one or
several discrete sources.
Defines the bypass type. The heat sink bypass option is associated
with an area ratio. The duct bypass option is associated with
a pressure drop coefficient in a off-branching duct.
Side fin cooling
Defines if the cooling of two extreme side is double sided or not.
The input window automatically out-selects combinations that
not are allowed.
The measures tab handles the physical dimensions of the heat sink. The
image makes it easy to check that the values are reasonable
set. One or several inputs can be inactive depending on how the
problem is defined.
The heat load tab handles the heat load. If the bottom plate is
isothermal it only has a single input line. If there are discrete
sources it is more detailed.
The heat sources are defined as rectangles. They are specified
in a table and can also be moved with the
mouse. Overlapping is allowed.
This tab is only visible if the given temperature
difference option has been selected. It is a simple
This tab is only visible if the fan option has
been selected as flow condition. The fan curve is a line train defined
by an arbitrary number of points. The curve can be saved,
various units can be used and the fan count can be controlled.
This tab is only visible if velocity has been selected as
flow condition. It is a single value input.
This tab is only visible if pressure drop has been selected as
flow condition. It is a single value input.
This tab is only active if the include radiation option
has been selected. The inputs are the emissivity
of the heat sink and the radiation environment temperature.
This tab defines the pressure loss coefficient for in the air duct
and the area ratio at bypass flow and the properties for
the bypass flow channel. Which one of these inputs that
are active depends on the problem definition.
Hsink presents the calculation result in a list with 15
columns which enables a very rich result
presentation. The list can be copied to a spread sheet program
which further expands the presentation possibilities.
Hsink can show and save the values generated by a
calculation in a rich collection of pre-defined diagrams.
The diagrams have a large number of appearance options. The
font, the background color, the margins and the scales can
all be controlled. An image of the heat sink, curve labels and
set up data can be included. The diagrams can be saved as GIF-files
and copied to the clip board. An exact width and height control makes
it simple to fit the diagram into a given space.
Hsink is based on analytical correlations for the
heat transfer coefficient and the pressure drop in rectangular
flow channels. Although this method has its constrains, it has
the advantage of being fast. The unique possibility to cover
a range of cases in each calculation would not have been possible
There is also has a unique ability to calculate heat sinks
in bypass flow. The theory for this procedure was developed as
a result of a cooperation with the
Applied Thermodynamics and Refrigeration
department at KTH in Stockholm.
Bottom plates with discrete heat sources are calculated by an
analytical three dimensional solution to the conduction equation.
Hsink creates intuitively understandable overviews in a
matter of a few minutes. To do anything corresponding with programs
that only calculate single cases takes hours. The code is
a great time saver.