A Summary of Findings of the Subcooled Liquid Flash Boiling Cycle and its Applications to Automotive Waste Heat Recovery.

DOI Web Site
  • Hewavitarane Dhaminda
    The University of Kitakyushu, Department of Mechanical Systems Engineering, Faculty of Environmental Engineering
  • Yoshiyama Sadami
    The University of Kitakyushu, Department of Mechanical Systems Engineering, Faculty of Environmental Engineering

Abstract

<p>In theory, automotive waste heat recovery (AWHR) is capable of offering a 15% improvement in engine system thermal efficiency. The SLFB Cycle is a novel heat cycle belonging to the family of Power Flash Cycles (PFC), and is capable of effectively converting the waste heat of automotive exhaust gasses into mechanical work. The power production efficiency ( ξ p) of PFCs has been shown to be higher by 14% ~ 29% than the Organic Rankine cycle and the SLFB cycle is expected to share this benefit. In experiments, the SLFB engine power output has been shown to increase in tandem with its thermal efficiency by increasing the convective boiling surface temperature up to the point of critical heat flux. In addition, increasing the boiling heat transfer surface area without increasing the dead volume can increases engine efficiency and power. Engine efficiency can also be improved by up to 20% if subcooled liquid injections into the boiling unit happen at constant pressure by the use of a split injection pattern. Engine efficiency and power output are heavily dependent on effectively removing any un-vaporised liquid (Residual Mass) from the convective boiling heat transfer surface during the exhaust stroke. Eliminating the Cyclic build-up residual mass effect can raise efficiency by up to 350%. If the expansion unit and boiling unit of the SLFB engine are detached, overheating of the block results in efficiency and power reductions. Thus, the temperature of the block should be maintained just high enough to achieve near adiabatic conditions at the maximum operating in-cylinder pressures.</p>

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top