Heatsink
Heat removal to the environment from power semiconductor devices.
blockType: AcausalElectricPowerSystems.Passive.Thermal.Heatsink
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Description
Block Heatsink simulates a radiator that dissipates heat from power semiconductor devices. The heat from the housing passes through the fins and is dissipated to ambient temperature due to convection. The description of the unit assumes that the environment is a working fluid.
In the block, it is possible to set parameters using tabular heat transfer characteristics or based on the geometry of the radiator using empirical formulas to describe convection. If the Convection parameter is set to Forced, then the flow rate through the input port v must be set.
Parameterization: tabular characteristics
To parameterize the block Heatsink using the tabular characteristics, set the Parameterization parameter to Datasheet and set the values of the parameters Vector of temperature rises above ambient, T and Corresponding heat dissipated to ambient, Q_TLU1(T).
If the forced convection mode is selected for the simulation (the Convection parameter has the value Forced - specify flow speed), then you need to set the values of the parameters Vector of temperature rises above ambient, T and Corresponding heat dissipated to ambient, Q_TLU2(T,v).
Parameterization: tabular values of convective heat transfer coefficients and rib efficiency
Set the Parameterization parameter to Tabulated convection and fin efficiency to parameterize the block Heatsink based on two parameters:
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the coefficient of convective heat transfer as a function of the fluid flow rate (for forced convection) and the difference between the temperature of the housing and the ambient temperature;
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the efficiency coefficient of the rib as a function of the coefficient of convective heat transfer.
The equation for calculating the dissipated heat is as follows:
,
where:
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— the heat transfer coefficient, set depending on the flow rate of the liquid (for forced convection) and the difference between the temperature of the housing and the ambient temperature;
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— the total surface area of the heat exchange;
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— the efficiency coefficient of the rib as a percentage, set depending on the coefficient of convective heat transfer. The efficiency coefficient of a rib is the ratio of the actual amount of heat dissipated by the rib to the amount of heat it would dissipate if its entire surface were at body temperature. This value depends on the geometry of the rib and its thermal conductivity.
Parameterization: rectangular parallel edges
If the Parameterization parameter is set to Assume rectangular parallel fins Then the block uses the following equations to calculate the dissipated heat:
,
where
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;
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;
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;
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— Rayleigh number;
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— the Reynolds number;
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m/s2 — acceleration of gravity;
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— coefficient of thermal expansion of the liquid;
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— kinematic viscosity of the liquid;
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— thermal conductivity of the liquid;
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— thermal conductivity of the liquid;
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— rib height;
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— rib length;
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— edge width;
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— the distance between the edges.
The total heat exchange area for edges in height and the cross section on , taking into account the fact that one side of the rib stands on the base of the radiator, it can be calculated using the formula:
.
The efficiency coefficient of a rectangular rib is determined by the formula:
,
where — thermal conductivity of the rib.
Ports
Parameters
Steady State
Parameterization — method of parameterization of
Assume rectangular parallel fins (default) | Datasheet | Tabulated convection and fin efficiency
The method of parameterization of the block, options to choose from:
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Assume rectangular parallel fins— calculation of parameters in the approximation of a radiator with rectangular parallel ribs (for more information, see [Parameterization: rectangular parallel ribs]). -
Datasheet— Parameterization is performed using tabular characteristics (for more information, see Parameterization: tabular characteristics). -
Tabulated convection and fin efficiency— Parameterization is performed using tabular values for convective heat transfer coefficients and rib efficiency (for more information, see Parameterization: tabular values of convective heat transfer coefficients and rib efficiency).
Convection — type of convection
Natural (by default) | Forced - specify flow speed
Choosing the type of simulated convection:
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Natural— modeling of natural convection. -
Forced - specify flow speed— simulation of forced convection, when selecting this parameter value, the v port appears in the block to set the flow rate.
Fin height — height of the pass edge:q[<br>] 0.0381 m (default) | positive scalar
Edge height.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Fin thickness — width of the pass edge:q[<br>] 0.00065 m (default) | positive scalar
The width of the edge.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Fin depth — length of the pass edge:q[<br>] 0.1397 m (default) | positive scalar
The length of the edge.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Gap between fins — the distance between the edges of the
0.0094 m (default) | positive scalar
The distance between the edges.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins, and for the Convection parameter , the value Forced - specify flow speed.
Number of fins — number of pass edges:q[<br>] 11 (default) | positive scalar
The number of edges. The value of this parameter must be equal to or greater than 1.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Fin thermal conductivity — thermal conductivity of the fin
237.0 W/(m*K) (default) | positive scalar
Thermal conductivity of the fins.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Vector of temperature rises above ambient, T — vector of values of the difference between the temperature of the housing and the ambient temperature
[10.0, 30.0, 50.0, 70.0, 90.0] To (default) | vector of positive scalars
The vector of values of the difference between the body temperature and the ambient temperature. The values of this parameter must be positive and strictly increasing.
Dependencies
To use this parameter, set the Parameterization parameter to Datasheet or Tabulated convection and fin efficiency.
Vector of fluid flow speed, v — vector of fluid flow velocity
[0.0, 1.0, 2.0, 3.0] m/s (default) | vector of positive scalars
The vector of the fluid flow velocity. The values of this parameter must be positive and strictly increasing.
Dependencies
To use this parameter, set the Parameterization parameter to Datasheet or Tabulated convection and fin efficiency, and for the Convection parameter , the value Forced - specify flow speed.
Corresponding heat dissipated to ambient, Q_TLU1(T) — the heat released into the environment corresponding to the difference between the body temperature and the ambient temperature
[6.1, 23.6, 44.5, 67.5, 92.3] W (default) | vector of positive scalars
The vector of values of the heat discharged into the environment, corresponding to the values of the difference between the temperature of the housing and the ambient temperature. The values in this parameter correspond to the values of the temperature difference in the parameter Vector of temperature rises above ambient, T. The values of this parameter must be positive and strictly increasing.
Dependencies
To use this parameter, set the Parameterization parameter to Datasheet, and for the Convection parameter , the value Natural.
Corresponding heat dissipated to ambient, Q_TLU2(T, v) — heat discharged to the environment, corresponding to the difference between the body temperature and the ambient temperature and the flow rate
[6.1 18.8 22.8 25.7; 23.6 61.1 73.0 81.5; 44.5 106.4 125.9 140.1; 67.5 153.5 180.7 200.3; 92.3 202.1 236.9 262.0] W (default) | the matrix of positive scalars
A matrix of values of the heat discharged into the environment, corresponding to the values of the flow rate and the difference between the temperature of the housing and the ambient temperature. The values in this parameter correspond to the values of the temperature difference in the Vector of temperature rises above ambient, T parameter.
Dependencies
To use this parameter, set the Parameterization parameter to Datasheet, and for the Convection parameter , the value Forced - specify flow speed.
Corresponding convective heat transfer coefficient, h_TLU1(T) — coefficients of convective heat transfer corresponding to the difference between the body temperature and the ambient temperature
[5.4, 7.02, 7.98, 8.68, 9.26] W/(m2*K) (default) | vector of positive scalars
The values of the coefficients of convective heat transfer corresponding to the values of the difference between the temperature of the housing and the ambient temperature.
Dependencies
To use this parameter, set the Parameterization parameter to Tabulated convection and fin efficiency, and for the Convection parameter , the value Natural.
Corresponding convective heat transfer coefficient, h_TLU2(T, v) are the coefficients of convective heat transfer corresponding to the difference between the body temperature and the ambient temperature and the flow velocity
[5.4 17.86 22.17 25.41; 7.02 19.49 23.8 27.03; 7.97 20.44 24.75 27.99; 8.68 21.15 25.46 28.69; 9.26 21.73 26.04 29.27] W/(m2*K) (default) | the matrix of positive scalars
The values of the convective heat transfer coefficients corresponding to the values of the body temperature and ambient temperature differences and flow rates.
Dependencies
To use this parameter, set the Parameterization parameter to Tabulated convection and fin efficiency, and for the Convection parameter , the value Forced - specify flow speed.
Vector of convective heat transfer coefficients, h — vector of convective heat transfer coefficients
[5.0, 10.0, 15.0, 20.0, 25.0, 30.0] W/(m2*K) (default) | vector of positive scalars
Coefficients of convective heat transfer. This parameter depends on the temperature difference caused by natural convection and the fluid flow velocity caused by forced convection. The values of this parameter must be positive and strictly increasing.
Dependencies
To use this parameter, set the Parameterization parameter to Tabulated convection and fin efficiency.
Corresponding fin efficiency (percent), eff_TLU(h) are the efficiency coefficients of the rib corresponding to the coefficients of heat transfer
[96.97, 94.16, 91.53, 89.08, 86.78, 84.62] ( by default) | vector of positive scalars
The efficiency coefficients of the rib, in percentages, corresponding to the coefficients of convective heat transfer. The efficiency coefficient of a rib is the ratio of the actual amount of heat dissipated by the rib to the amount of heat it would dissipate if its entire surface were at body temperature. This value depends on the geometry of the rib and its thermal conductivity.
Dependencies
To use this parameter, set the Parameterization parameter to Tabulated convection and fin efficiency.
Total heat exchange surface area — total heat exchange surface area
0.1171 m2 (default) | positive scalar
The total surface area of the heat exchange.
Dependencies
To use this parameter, set the Parameterization parameter to Tabulated convection and fin efficiency.
Fluid Properties
To use this parameter group, set the Parameterization parameter to Assume rectangular parallel fins.
Fluid kinematic viscosity — kinematic viscosity of the liquid
1.51e-05 m2/s(default) | positive scalar
Kinematic viscosity of a liquid.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Fluid thermal diffusivity — thermal conductivity of the liquid
2.07e-05 m2/s(default) | positive scalar
Thermal conductivity of the liquid.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Fluid thermal conductivity — thermal conductivity of the liquid
0.025 W/(m*K) (default) | positive scalar
Thermal conductivity of the liquid.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Fluid coefficient of volume thermal expansion — coefficient of thermal expansion of the liquid
0.0033 1/K (default) | positive scalar
Coefficient of thermal expansion of the liquid.
Dependencies
To use this parameter, set the Parameterization parameter to Assume rectangular parallel fins.
Links
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Churchill, Stuart W.; Chu, Humbert H.S. Correlating equations for laminar and turbulent free convection from a vertical plate. International Journal of Heat and Mass Transfer (November 1975): 1323-1329.
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Teertstra, P., Yovanovich, M.M., and Culham, J.R. Analytical Forced Convection Modeling of Plate Fin Heat Sinks. Proceedings of 15th IEEE Semi-Therm Symposium (1999): pp. 34-41.