Simulations Used to Develop Smokeless Fire Pits

The HPC Behind the Product

The HPC Behind the Product Series

May 4, 2021

There is something special about the crackling of the open flame of a bonfire. Before the recent invention of portable smokeless fire pits, those of us who live in a city or tightly spaced urban environment have not been able to enjoy a fire pit. Modern science has come to the rescue once again with the development of portable fire pits such as those from Solo Stove® and Breeo, helping us relive the magic of the bonfire in the comfort of our back yard or balcony.solo stove bonfire

Computer modeling and simulation played a large role in bringing the portable open-flame bonfire fire pit concept to the urban environment, where open flames and the strong smell of smoke are usually not acceptable.  Engineers and scientists designed portable fire pits to not only make the experience enjoyable for the user but also in such a way as to keep the user and surrounding environment safe.

At approximately 20 lbs, Solo Stove’s Bonfire stove model is a lightweight structure and measures 19.5” in diameter and roughly 14” in height.  It is built as a dual wall, 304 stainless steel sheet metal structure that creates two burn areas: primary combustion at the bottom of the stove where the firewood is located and a secondary combustion at the top of the burn chamber.

What makes the near smoke-less burn in the stove possible?

As the wood starts burning in the primary combustion chamber hot air rises towards the top of the stove depleting the environment of oxygen needed to sustain the burning process. This combustion process pulls cold air in through the bottom vent, a circular hole pattern at the bottom of the stove. The air movement fuels the fire in the primary combustion area and provides a boost of preheated air to the secondary combustion chamber. The preheated air rises between the double-wall steel before flowing into the chamber through the vent holes at the top. This preheated oxygen causes a secondary combustion, essentially burning off any remaining fuel suspended in the air. In other words, the Bonfire stove burns the smoke, leaving very few particulates to be exhausted on top of the stove. The fire ring at the top of the stove also helps to keep the fire centered and promotes a hotter burn.

An ash pan is welded directly to the stove’s bottom collecting the falling ashes as the wood burns preventing ashes from choking the airflow.  The primary combustion area is located on top of a perforated precision base plate located above the ash pan. The trick of achieving an almost smokeless, hot fire is the airflow pattern in the Bonfire.

What keeps the Bonfire’s resting surface from catching fire?

The ash pan acts as a radiative heat shield preventing the fire pit from damaging the surface the stove is resting on. This allows the Bonfire stove to be used on almost any surface without the risk of fire.  To achieve such balanced airflow with high combustion efficiency, development engineers use complex Multiphysics simulations that allow them to not only visualize the performance of their designs but also to automate the optimization process. The image below shows flow lines from burning wood in a dual wall smokeless portable fire pit, something that cloud computing enables the engineers to “see” during the design process.

Fire pit simulation

A burning pattern in a dual wall portable smokeless fire pit visualized using CFD simulation in the cloud

Without simulation tools, intricate test rigs would have to be developed and observed in real-time without the convenience of reviewing and analyzing the results later.  It is safe to say that cloud computing helps simulation engineers push the boundaries of science and create products that enrich our lives. More to come, as the possibilities that cloud computing creates are truly limitless.

Next on deck in our HPC Behind the Product series, is the YETI tumbler.

Disclaimer: We are not affiliated, associated with, or in any way represent Solo Stove.

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