Turbine Stove

This idea originated out of failures experienced with camping stoves currently on the market that use thermoelectric generators and fans to boost the output of biomass fires. I found purchase prices and failed part replacement costs prohibitive, and envisioned a different, more literal way to turbocharge a wood fire.

The stove uses two coupled turbines and a venturi to force airflow into the stove, increasing the heat and efficiency of combustion to produce a clean-burning, high-heat flame for cooking. Alternatively, the turbine shaft could be linked to a generator for small-scale or emergency power production using fuels as diverse as pellets, manure, grass, twigs, or other readily available combustibles.

Initial concept

The two turbines are connected by a shaft housed within a protective tube. The main body incorporates a venturi shape, designed to increase the flow rate of hot gasses as they pass through the exhaust turbine. In this sketch, the turbines and body would be expensive to manufacture, and the venturi is incorrectly positioned relative to the exhaust turbine.

CAD design

The stove was designed using top-down modelling techniques and master sketches. This method made it simple to control the fitment between components (many are press-fit for simple, inexpensive assembly), easier to make iterative improvements to the model, and effortless to construct the final assembly.

Function

Exhaust gasses from fuel burning in the central chamber rotate the exhaust turbine, thereby rotating the intake turbine and forcing oxygen into the stove through openings in the base. This forced induction boosts the heat and completeness of combustion, increasing gas expansion within the stove. The constricting stove walls form a venturi that further increases the velocity of the rising gasses, more forcefully accelerating the exhaust turbine.

In this manner, the turbines continue to accelerate, and the stove burns with increasing intensity, until rising gas pressures within the stove and increasing thermal and friction losses stabilize the angular velocity of the turbines.

Latest iteration

  • Component breakdown top to bottom: exhaust hub, exhaust turbine, bolts, exhaust support, exhaust screen, bearing, shaft and protective tube, bearing, intake screen, intake support, bolts, intake turbine, intake hub, main body and door.
  • The main body, access door, and turbine shaft supports are modeled to be stamped and formed from sheet metal to minimize costs. All components assembled with rivets (not shown).
  • The turbine blades are designed to be stamped and formed from one piece of sheet metal, then bolted to the hubs. This eliminates the need for machined blades, which keeps costs down.
  • Bearings, bolts, and shaft are standard sizes, readily available from suppliers like McMaster-Carr, also to minimize costs.
  • The two screens are nonspecific: any screen will serve, so long as it is tolerant to high heat, promotes airflow, and can protect the blades from debris.
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