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Designing a More Effective Car Radiator
The challenge: To determine the design parameters of a smaller radiator assembly capable of dissipating the same amount of heat as the original assembly.
© Maplesoft, a division of Waterloo Maple Inc., 2008

Executive Summary Introduction Problem Definition 1. Original & Proposed Radiator Dimensions 2. Heat Transfer Performance of Proposed Radiator 3.Adjusting Heat Transfer Performance of Proposed Radiator 4. Export Optimized Radiator Dimensions to SolidWorks Results

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Executive Summary
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 throughcombustion 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 heattransfer performance. Most four-cylinder automobiles, depending on their size, have radiator cores that vary from

19''# 11.5''# 0.7'' to 27''# 17''# 0.9''. We believe that we can greatly reduce the size of automotive
radiators while maintaining the current levels of heat transfer performance expected. Moreover, this can be done without significant modification to the existing internal radiatorstructure. There are several different approaches that one can take to optimize the heat transfer performance of a smaller radiator design. 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. The latter method was chosen for our proposeddesign. To prove this hypothesis, we conducted tests on our current radiator assembly, which measures

24''# 17''# 1'', to determine the heat transfer performance under typical operating conditions. We found our Btu J current radiator assembly to be capable of dissipating heat at a rate of 4025 70729 . Next, minute s using the ε-Ntu (effectiveness-Ntu), we calculated the heat transfer performanceof our new radiator assembly, which has a radiator length 30% smaller than the length of the current design (18''# 17''# 1''). As expected,
the heat transfer performance decreased. However, by increasing the metal-to-air surface area from 384 fins per row to 437 fins per row, we increased the heat transfer performance of our proposed design to the same level as the current design under the sameoperating conditions.

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Introduction
In an automobile, fuel and air produce power within the engine through combustion. Only a portion of the total generated power actually supplies the automobile with power -- the rest is wasted in the form of exhaust and heat. If this excess heat is not removed, the engine temperature becomes too high which results inoverheating and viscosity breakdown of the lubricating oil, metal weakening of the overheated engine parts, and stress between engine parts resulting in quicker wear, among other things. A cooling system is used to remove this excess heat. Most automotive cooling systems consists of the following components: radiator, water pump, electric cooling fan, radiator pressure cap, and thermostat. Ofthese components, the radiator is the most prominent part of the system because it transfers heat.
Figure 1: Componets within an automotive cooling system

As coolant travels through the engine's cylinder block, it accumulates heat. Once the coolant temperature increases above a certain threshold value, the vehicle's thermostat triggers a valve which forces the coolant to flow through the...
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