Thermal Design - Walmate Thermal

What is a thermal design?

Thermal design can be defined as a systematic design approach implemented during the initial phase of thermal management planning. Its core lies in leveraging advanced software tools to conduct comprehensive computer-aided simulation analyses, with the ultimate goal of generating reliable theoretical data.In practice, this method begins by identifying key variables that influence thermal performance, such as the material and structural parameters of heat sinks, the flow channel design of liquid cooling plates, the rotational speed and air volume of fans, as well as material properties, heat source intensity, and environmental conditions. Engineers then adjust and set these diverse parameters within the simulation software, creating multiple virtual scenarios that mimic real-world operating environments—for example, testing the impact of different heat sink sizes on local temperatures, or altering the combination of coolant flow rates in liquid cooling plates and fan operating power to observe changes in the overall heat dissipation efficiency of the system.

The purpose of thermal design.

The purpose of thermal design is to identify potential risks of chip overheating and find optimal solutions. It involves using software calculations to support product prototyping, verifying results through final tests, and further optimizing based on those findings.However, many engineers—especially newcomers—are unclear about the reasons for conducting thermal design and simulation. They often start working merely to complete tasks without first understanding the objectives and requirements. This approach leads to issues such as missing necessary conditions or using incorrect methods, resulting in significant time waste. Ultimately, they may even question the validity of their results.Thus, the ultimate goal of thermal design for electronic products is to continuously refine the optimal project solution through theoretical calculations, simulation analyses, and experimental testing. This ensures the long-term stable operation of electronic products, preventing equipment malfunctions caused by component overheating.

The significance and value of thermal design.

In other words, why do we need to conduct thermal design simulation analysis. This is mainly reflected in three aspects: reducing costs, shortening research and development cycles, and improving product reliability and competitiveness. Reducing costs mainly manifests in reducing the cost of back and forth sampling and the time cost of repeated testing. Shorten the research and development cycle, quickly validate heat dissipation solutions (such as duct layout and material selection) in virtual environments, and reduce the number of sampling times. A certain enterprise extended the thermal runaway protection time from 58 seconds to 220 seconds through simulation, without the need for repeated trial production. Improve product reliability and competitiveness. We know that if there are design defects or selection issues, it will lead to abnormal equipment operation. If we can understand the design defects in advance, identify the thermal weak areas of electronic components inside the equipment, and optimize and improve their design, it will greatly enhance the reliability of the product in harsh environments and improve its competitiveness.

Walmate can help customers to do a heat sink thermal design.

We are capable of providing customers with thermal design services for heat sinks. Typically, when a customer selects a chip, their engineers can supply us with the chip’s specifications, such as its thermal power in watts. Our engineers then perform theoretical calculations to determine the appropriate heat sink solution.The size of the heat sink is largely dictated by these calculations. For chips with high power consumption, we often consider forced convection solutions. Conversely, for low-power chips, natural convection designs are usually sufficient. Through these theoretical computations, we can approximate the required length, width, height, and surface area of the heat sink.We then simulate different air flow rates and pressures to calculate the maximum temperature the chip would reach when paired with the designed heat sink. This theoretical design approach helps customers save significant development time and costs by avoiding unnecessary trial-and-error with physical prototypes.

Walmate can help customers to do a liquid cooling plate thermal design.

We Similarly, we can also design a thermal solution involving liquid cooling plates for customers. When a customer’s chip operates at extremely high power levels—exceeding the cooling capacity of conventional heat sinks paired with fan,we turn to liquid cooling plates, leveraging the high specific heat capacity of water. This design allows water or coolant to circulate through the interior of the liquid cooling plate, effectively transferring and dissipating large amounts of heat: the heat generated by the chip is absorbed by the coolant, which is then pumped away by a water pump to remove the accumulated thermal energy.In designing such liquid cooling plates, we start with the theoretical power requirements to engineer a suitable solution, including the design of microchannels in the area directly beneath the chip. Through repeated parameter adjustments and simulations, we can achieve the target temperature specified by the customer. This approach also saves significant costs and development time.Thermal design is therefore crucial in liquid cooling plate development, especially given the high manufacturing costs of such components. By using software for simulation and analysis, we can drastically reduce research and development expenses, making the process both efficient and cost-effective.

Thermal design FAQs

How to do a heat sink therml design?

When designing a thermal analysis for a heat sink, it is usually necessary to clarify whether it is for natural convection or forced convection.In the case of natural convection, the heat sink must take full account of the space between the fins, which is the space for radiative heat exchange. Meanwhile, we must also consider gravity and radiation as parameters. Therefore, in thermal design, these two parameters – gravity and thermal radiation – are of great importance. Typically, the surface of the heat sink should be black, with its emissivity usually set at 0.8.On the other hand, for a forced convection heat sink, the PQ curve of the fan should be analyzed using the system's imported model. In this scenario, radiation and gravity do not need to be considered for the heat sink.In summary, these two factors are generally the most important considerations when designing a heat sink.

How to do a liquid cooling plate therml design?

When designing a liquid cold plate, we usually need to consider its material and whether microchannels are required – which is determined by the power density within the limited area. Simply put, if a 100×100 area needs to handle a thermal power of over 1 kilowatt, microchannel design at the bottom of the heat source is essential. This allows the cooling liquid to fully exchange heat with the microchannels, effectively dissipating large amounts of heat.Therefore, in the design of a liquid cold plate, the flow channel design is a key consideration. It is also necessary to take into account the total length of the flow channel, with particular attention to two crucial parameters: pressure difference and flow resistance. These parameters are vital for the end - user's chiller.In conclusion, we need to comprehensively evaluate these three aspects (material, microchannel necessity, and flow channel - related parameters) to achieve an optimal design.

How to do a heat pipe heat sink thermal design?

When designing a heat pipe heat sink, we usually need to determine the heating power and select heat pipes of appropriate diameters. For instance, diameters like 6mm, 8mm, or 9.52mm are commonly used.If the power is low and the area is relatively large – meaning there is sufficient space for arranging heat pipes – we can usually choose heat pipes with an outer diameter of 6mm. If the space is limited, we need to select heat pipes with a larger diameter, such as 9.5mm. This is because heat pipes of different diameters can carry away different amounts of heat within an effective length.Therefore, when setting the thermal conductivity of heat pipes, based on experience, we set it to 12,000 - 15,000 W/(m·K). This is quite close to the parameter values in practical applications, with little difference.The only difference is that in actual applications, there is the influence of gravity. That is why there is a relatively large difference between the heat simulation of heat pipes and the actual situation. So this must be avoided as much as possible during the design process. The impact of gravity on heat pipes in later practical use must be considered in the early stage.

How to do a skived fin heat sink thermal design?

When designing a skived fin heat sink, material is a key consideration. For example, the thermal conductivity of 1060 aluminum is typically set at 240 W/(m·K), while that of 6063 aluminum is usually 187 W/(m·K).Accordingly, we need to optimize the thickness, height, and spacing of the fins to find the optimal parameters. If the heat sink is required to handle ultra-high power, such as over 1 kilowatt, the fin thickness should theoretically be greater than 1.0 mm.When the fin height exceeds 100 mm, due to the excessive size, sufficient thickness is needed to ensure heat transfer from the bottom to the top of the fins. In such cases, we generally set the fin thickness to 1.5 mm and then adjust the spacing accordingly.Theoretically, an optimal fin spacing might be between 1.0 mm and 2.5 mm in design, but in practice, a thickness of 1.5 mm is necessary to ensure heat can conduct to the top of the fins. Of course, accurate heat sink design requires extensive data analysis based on practical applications.

What are the typical levels of thermal design?

Thermal design simulations typically fall into four levels.The first is system - level simulation, which focuses on thermal analysis of the entire system, such as large cabinets or equipment, involving the simulation and analysis of the overall temperature field and fluid flow field. This kind of analysis is usually complex. For example, when dealing with a large inverter cabinet, which generates a significant amount of heat, the simulation needs to consider the impact of each heat source on the entire system.Next is board - level or module - level simulation. This generally refers to the analysis of heat distribution in a single heat sink, temperature analysis inside a module, and temperature simulation of components. The key here is to focus on the thermal analysis of high - power large modules.Then there is PCB - level simulation. It usually involves simulating the layout of copper traces on the PCB and the temperature of chips on the board. In other words, when designing a PCB, the rationality of the trace routing at the bottom of the board and the placement of each component is analyzed. Since there is a copper film on the PCB, if the design is too concentrated, the heat generated will affect other components. Therefore, a reasonable PCB simulation analysis is very helpful for electronic engineers, as it can guide them to arrange the PCB layout properly.The last one is IC - level simulation. This level focuses on the analysis of the temperature field inside a chip, that is, the distribution of heat - generating components within a chip, which is crucial for packaging engineers. They can analyze the heat generated by thousands of stacked chips at this stage. However, IC - level or chip - level simulation is very difficult for preliminary design engineers. This is because packaging factories usually do not provide parameters such as the actual power inside the chip. Only industry giants like Intel, IBM, IMD, or NVIDIA conduct such analyses.In general, most of the simulations we perform are at the IC level, PCB level, module level, and system level. Each engineer has different areas of focus, so their work priorities also vary.

How to optimize the thermal design of a heat sink?

The design optimization of a heat sink usually starts with the power of the chip to determine the thickness of the heat sink base, which is crucial. When the power is high (over 1 kilowatt), the base thickness must be more than 12–15 mm.Next, optimizing the thickness, height, and quantity of the fins is equally important. For example, if the fin length exceeds 300 mm, it is theoretically advisable to split the fins in the middle. This creates turbulent airflow, thereby enhancing heat dissipation efficiency.Another key aspect is optimizing the air duct: reducing wind resistance inside the duct and avoiding airflow short circuits (such as the formation of eddies) that would waste a significant amount of air volume.Additionally, the size and position of the inlet and outlet openings are important, especially at the system level. A well - designed opening allows airflow to pass through efficiently, helping maintain a reasonable temperature across the entire system. However, the opening size must also consider other environmental factors, such as dust prevention, making it a complex design process.

How to optimize a liquid cooled plate during thermal design?

When optimizing and simulating the design of a liquid cold plate, it is usually necessary to consider the entire cooling system, including the coolant, medium, liquid cold plate, and water pump.The first parameter involves selecting an appropriate coolant. Options such as ethylene glycol mixed with water, propylene glycol mixed with water, ethanol mixed with water, liquid metals, or pure water are commonly considered. The choice of coolant is crucial for the entire circulation system. Structurally, we need to take into account the requirements for heat exchange performance. That is, under the set conditions of flow rate and temperature difference between inlet and outlet, we aim to improve the heat exchange efficiency. Additionally, the requirements for pressure resistance and structural strength of the liquid cold plate surface must be considered.In the design process, optimization should be made for the thickness of the liquid cold plate. Other factors like anti-corrosion and anti-leakage requirements also need attention. During thermal design, the design of the cold plate's cover and upper/lower end faces must be taken into account. If a sealing strip is used, its strength should be considered; when welding is involved, the actual processing difficulty should be evaluated.Finally, a reasonable design scheme should be developed, and optimal production processes should be adopted to reduce costs. All these factors must be considered in thermal design.

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