#cfd modeling

How CFD Simulations Support Sustainable Data Center Design Optimization

Atrium smoke extract represents critical life safety HVAC design requirements for managing smoke in large-volume spaces during fire emergencies through systematic smoke removal and clear air preservation. Professional standards provide comprehensive methodologies for calculating smoke extraction rates, managing buoyancy-driven smoke movement, and coordinating with building fire protection systems…

Datacenter Case Study – Minimizing lost IT loading capacity through the virtual facility approach

by Sherman Ikemoto

The initial capital cost of a data center facility runs anywhere from $10 to $30 million per megawatt of IT capacity. Despite these high costs, the average data center strands between 25% to 40% of its IT loading capacity through inefficient data-center equipment layout and management. As such, substantial financial losses are routinely incurred through lost IT loading…

Mechanical engineering design has grown from leaps and bounds in recent times. We are seeing mechanical engineering highly reliant on 3D CAD and virtual simulation. But computational fluid dynamics has not been utilized fully by mechanical design engineers. The reason for that being CFD is a very expensive process with different complications and it is difficult to integrate it with other 3D mechanical design tools. But things are changing and we are now seeing CFD being available at a very reasonable cost. The entire process of CFD simulation has also altered thereby making way for fluid flow both inside and outside around a 3D object.

CAD embedded CFD software has gained lots of prominence recently which has enabled engineers to not only concentrate on fluid flow but also thermal dynamics and other design tasks. There are times when mechanical engineers succumb to pressure and slow down on the design process thereby enabling errors to creep up. There are various benefits of including simulation in the early stages of design. With the help of CFD simulation, it is possible to reduce the number of test sessions, prototypes, and post-release modifications. Mechanical engineers will use thermal analysis and FEAs as a mechanical design tool rather than CFD even though fluid flow is really important for design of modern equipment.

With the help of computational fluid dynamics (CFD) it is possible to have a detailed and through approach that can be used as a benchmark. It is different than traditional methods. It uses complex algorithms based on non-linear, discrepancy equations, geometric calculations, and central laws of physics and even chemistry. It can also help in getting differential temperatures, fluid flow velocity and electrolyte concentrations, which can be used to modify the design. CFD is an important component in the mechanical design of a product.

Hence, it is often regarded at the center stage of mechanical design.

Computational Fluid Dynamics (CFD) is a perfect tool for studying rotating components. A glance at such disparate machines such as pumps, table fans, axial fans for electronic cooling and hair dryers, shows that they all have one thing in common: rotating components.

Engineers who design equipment with rotating components need to analyze and understand the behavior of those components if they want to improve performance. For example; if the blades of the table fan are in the wrong shape or if they’re incorrectly oriented, the fan may generate little to no air.

CFD helps engineers study many of the issues involved in rotating component behavior. It provides a way to save a great deal of time and money in obtaining the necessary information, and assists engineers in designing better quality rotating equipment.

The use of CFD makes it possible to eliminate expensive physical prototypes, and find serious flaws much earlier in the design process. Starting with CFD basics, this article will give engineers an overview of how users of HiTech CFD can solve typical problems.

Several different approaches can be used to study flow in and around rotating equipment. In the majority of rotating machinery fluid-flow analyses, engineers model the flow in a steady-state manner. The term “steady-state” refers to a solution that does not vary with time.

A very simplified approach called Single Rotating Reference Frame, which assumes that the entire fluid domain or region rotates with the rotor or impeller, can be used to study the flow around the impeller blades. However, because this doesn’t consider any effects of the pump casing on the flow, it is insufficient for analyzing a full pump system.

To study the whole flow pattern and see the effects of the stationary pump casing, baffles, and other internal parts, users need more comprehensive methods, such as Multiple Rotating Reference Frame, also a steady-state approach, the engineer assigns zero revolutions per minute (RPM) to nonrotating components, called stators, and fixed RPMs to the rotating components, called rotors. With this method, users can consider more than one rotor, each rotating with a different RPM.

The Sliding Mesh method is a transient approach that is useful for rotating flow problems requiring a time-accurate solution for computing the unsteady flow field. It requires a very large number of time steps to arrive at the transient solution, making the process time-consuming as well as computationally demanding, and may turn out to be impractical on desktop computers.

HiTech CFD Simulation uses both the single and multiple rotating reference frame approaches to solve rotating flow problems. Overall, the program employs configuration-based fluid-flow analysis coupled to SolidWorks software assembly configurations to enable a wide variety of “what if” scenarios. Every flow study either creates a new configuration or can link to an existing SolidWorks software configuration. The software aims to solve the majority of possible rotating equipment problems, and to do so quickly. For the sake of speed, HiTech CFD Simulation does not use the transient approach.

Computational Fluid Dynamics (CFD) simulation has always been considered a very difficult subject to handle. But now things are changings quite rapidly. We are seeing lots of changes in the way CFD is being persuaded. Now people are keener on understanding the benefits of CFD ignoring the negative points. But there is still a section in the audience that has lots of doubts regarding CFD. In this article; we will look at some of the myths regarding CFD and the realities associated with it. So let us start off the journey: Myth:CFD is very complex to be used in design process Reality: It has been found that there are many mechanical engineers who are not familiar with CFD tools which was quite an astonishing fact to learn. But now things have changed radically.  Since a decade or so there has been a growing impetus amongst mechanical engineers to learn about CFD tools and we are now seeing deep awareness of CFD in them to get adequate results. New technology has enabled the use of CFD software quite easy and we are now seeing that mechanical engineers are using this tool quite easily as the manual tuning feature has been removed totally and now everything is automatic. The only thing that a mechanical engineer needs to know while using CFD tools is adequate knowledge of CAD system and physics of the product. Myth: It takes a lot of time to use CFD in the designing process Reality: We have already discussed that earlier CFD software had to used manually hence it used to take lot of time in meshing process. But since the new version has been launched everything has become automatic and now with the help of 3D CAD data is directly used for fluid flow simulations without the need for translations or copies. The automatic mesher as discussed earlier creates the mesh while maintaining the skewness and aspect ratio hence; there is no need for any manual work. The results are quite quick and design changes can be meshed within minutes. Hence; this is absolutely incorrect to say that it takes lot of time to use CFD in the designing process. Myth: CFD is costlier hence; it cannot be used by mechanical engineers Reality: Earlier version of CFD software used to be very expensive to purchase by mechanical engineers as traditional CFD costs used to cost $ 250,000 to lease per year. But with the latest version of CFD software this is not true. Now this software can be assessed for $ 25,000 at perpetual license with an yearly maintenance fees of 18%. This software requires minimal training and is very user friendly. This software can be assessed using the same CAD environment as the engineers are familiar with hence; it is very useful. Moreover, it can run easily on computer and laptops at a very reasonable cost.