The demand for more powerful engines in smaller hood spaces has created a problem of insufficient rates of heat dissipation in automotive radiators. Upwards of 33% of the energy generated by the engine through combustion is lost in heat. Insufficient heat dissipation can result in the overheating of the engine, which leads to the breakdown of lubricating oil, metal weakening of engine parts, and significant wear between engine parts. To minimize the stress on the engine as a result of heat generation, automotive radiators must be redesigned to be more compact while still maintaining high levels of heat transfer performance.

There are several different approaches that one can take to reduce the size of automotive radiators while maintaining the current levels of heat transfer performance expected. These include: 1) changing the fin design, 2) increasing the core depth, 3) changing the tube type, 4) changing the flow arrangement, 5) changing the fin material, and 6) increasing the surface area to coolant ratio.

By increasing the surface area to coolant ratio, this application shows how one can minimize the design of a radiator and still have have the same heat dissipation as that of a larger system, given a set of operating conditions.

Figure 1: Components within an automotive cooling system

The dimensions of our original radiator design can be extracted from the SolidWorks® drawing file (CurrentRadiatorDrawing.SLDPRT). The drawing is a scaled down version of the full radiator assembly which measures $24\'\'\times 17\'\'\times 1\'\'$.  For the purpose of our analysis, the dimensions obtained from CAD are scaled up to reflect the radiator's actual dimensions.

Note: This application uses a SolidWorks design diagram to extract the dimensions of the original radiator. This design file can be found in the data directory of your Maple installation, under the subdirectory SolidWorks. If you have SolidWorks version 8.0 or above, save the design file, and then click the radio button below to tell Maple™ where to find the file. If you do not have SolidWorks installed on your computer, the values will be pre-populated.

Figure 2: CAD rendering of current Radiator Model

Original Radiator Model Dimensions

The table below summarizes the current radiator dimensions.   Current Radiator Dimensions Radiator length $\left(\mathrm{rL\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$ Radiator width  $\left(\mathrm{rW\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$ Radiator height $\left(\mathrm{rH\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$ Tube width $\left(\mathrm{tW\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$ Tube height $\left(\mathrm{tH\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$ Fin width $\left(\mathrm{fW\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$ Fin height $\left(\mathrm{fH\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$ Fin thickness $\left(\mathrm{fT\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$ Distance Between Fins $\left(\mathrm{fD\_\_cur}\right)\:$  $\mathrm{ft}$   $m$$$           Number of tubes $\left(\mathrm{ntube\_\_cur}\right)\:$                            $$   Testing this radiator design under different coolant flow and air flow conditions yielded the following graph of heat transfer performance vs. coolant flow rate at different airflow speeds.   A heat transfer performance of $4025 \frac{\mathrm{Btu}}{\mathrm{minute}}$ was obtained using a coolant volumetric flow, air volumetric flow and air velocity of $30 \mathrm{gpm}\, 2349 \frac{{\mathrm{ft}}^3}{\mathrm{minute}}\, 10 \frac{\mathrm{mi}}{h}\,$respectively.   These results are summarized in the table below.     Figure 3: Heat transfer performance vs. coolant flow rate at different airflow speeds   $$ Radiator Operating Conditions Coolant Volumetric Flow $\left(\mathrm{vf\_\_c}\right)\:$$$  $\mathrm{gpm}$        $\frac{m^3}{s}$ $$ Air Volumetric Flow $\left(\mathrm{vf\_\_a}\right)\:$  $\frac{{\mathrm{ft}}^3}{\mathrm{minute}}$  $\frac{m^3}{s}$ $$ Air Velocity $\left(\mathrm{v\_\_a}\right)\:$  $\frac{\mathrm{mi}}{h}$$$         $\frac{m}{s}$ $$ Heat Transfer Performance $\left(\mathrm{q\_\_cur}\right)\:$ $\frac{\mathrm{Btu}}{\mathrm{minute}}$    $\frac{J}{s}$ $$

Proposed Radiator Model Dimensions

Our proposed design has a radiator length that is 30% smaller than that of the original model.  The dimensions of the radiator core (radiator length, radiator width and radiator height) can be adjusted to any dimension.   The table below summarizes the radiator dimensions for our proposed design. $$ Proposed Radiator Dimensions Radiator length $\left(\mathrm{rL\_\_new}\right)\:$$$  $\mathrm{ft}$ $m$$$ Radiator width  $\left(\mathrm{rW\_\_new}\right)\:$$$  $\mathrm{ft}$  $m$$$ Radiator height $\left(\mathrm{rH\_\_new}\right)\:$$$  $\mathrm{ft}$  $m$ $$$$ Tube width $\left(\mathrm{tW\_\_new}\right)\:$$$  $\mathrm{ft}$  $m$ $$ Tube height $\left(\mathrm{tH\_\_new}\right)\:$$$  $\mathrm{ft}$  $m$ $$ Fin width $\left(\mathrm{fW\_\_new}\right)\:$$$  $\mathrm{ft}$  $m$ $$ Fin height $\left(\mathrm{fH\_\_new}\right)\:$$$  $\mathrm{ft}$  $m$$$ Fin thickness $\left(\mathrm{fT\_\_new}\right)\:$  $\mathrm{ft}$  $m$ $$ Distance Between Fins $\left(\mathrm{fD\_\_new}\right)\:$$$ $\mathrm{ft}$  $m$          Number of tubes $\left(\mathrm{ntube\_\_new}\right)\:$$$             $$   $$

	Coolant and Air Property Tables
	The thermal fluid properties for the coolant and air are listed in the following two tables.   Coolant Properties: 50-50 Glycol-Water Thermal conductivity $$