Microwave Engineering Europe - December 2007 - (Page 30) 30 THERMAL ENGINEERING Keeping cool with increasing power to density ratios Microwave technology specialist Milmega is using CFdesign flow and thermal simulation software during early stage product development to optimise the design of its cooling systems and get new products to market in record time. By Milmega Ltd T he evolution of electronic equipment has generally been driven by the desire for ever smaller, more powerful products. This presents a number of ongoing challenges for everyone involved in their design and manufacture, not least those charged with keeping the products cool. Smaller, more powerful electronic products generate more heat yet contain minimal space for effective air circulation and thermal management. Increasingly, manufacturers such as Milmega Ltd are choosing to optimise the design of their cooling systems using upfront computational fluid dynamics (CFD) software from Blue Ridge Numerics. Established in 1987, Milmega designs, develops and manufactures solid state high-power broadband amplifiers for a wide range of industry applications including communications testing, defence and medical. These amplifiers enable Milmega’s customers to increase the power of an initial RF (radio frequency) source until it falls within the specific waveband appropriate for its eventual application. One of the qualities that sets Milmega apart from its competitors is the compact size of its amplifier units. Indeed, the company has always aimed to achieve the greatest power to density ratio of anyone in the industry and its latest product range is a quarter of the size of other units on the market today. But while this goal creates a distinct commercial advantage, it presents the company’s thermal engineers with a constant challenge. Figure 1: Pressure section. Cohesive design Milmega achieves its goal of small scale, high power amplifiers through a design style it calls CSA – corporate structure architecture. Clive Hodson, Lead Mechanical Engineer at Milmega, explains: “We design each unit as a cohesive whole. Rather than one group designing the modules, another fitting the combiners, someone else the dividers and yet another the drivers, we bring the whole team together to work on a design that flows through the unit without wasting space.” For this system to work effectively, it is vital that Hodson and his team address any potential thermal issues right at the beginning. For companies where space is not such a driver, it is always possible to add an extra fan at the last minute if necessary, but not at Milmega, so upfront CFD electronics cooling simulation has become an essential part of the process. “Upfront analysis is very important here,” says Hodson, “particularly with new products. We have to iron out any potential problems right at the beginning and ensure we are maximising our use of available space.” Upfront CFD Over the past year, to aid the development of a new product range, Milmega has been using CFdesign from Blue Ridge Numerics. This powerful upfront CFD simulation tool enables multiple flow simulations to take place right at the beginning of the product development process, creating a more dynamic development cycle, reducing costs and improving time to market. CFdesign wasn’t Milmega’s first foray into CFD simulation, but it has certainly been the most successful: “We used to use an older CFD software, but it became very frustrating,” explains Hodson. “It Microwave Engineering Europe ● December 2007 ● www.mwee.com 030-031_MWEE.indd 30 23/11/07 12:01:55 http://www.mwee.com
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