## Abstract

The present study focuses on the accurate determination of local heat flux distributions encountered in aero propulsion convective heat transfer studies. Heat transfer surfaces constructed for use in steady state techniques typically use thin foil type heating elements to generate a constant heat flux surface. Many of the previous studies have relied on rectangular foil shapes that generate a uniform surface heat flux distribution. Other studies that deal with geometrically complex heating elements have omitted the nonuniform heat flux regions or applied correctional techniques which are approximate. The current study combines electric field theory and a finite element method based on variational principles directly solve for an arbitrarily specified surface heat flux distribution. Local electric energy generation per unit volume of the surface heater element in the form of local Joule heating is calculated using a differential method. The technique is shown to be applicable to many convective heat transfer configurations common in aero propulsion devices. These configurations often have arbitrarily specified external and internal geometrical boundaries such as turbine passage endwall platforms, surfaces disturbed by the existence of film cooling holes, blade tip sections, etc. A complete steady state heat transfer technique that makes use of the present local heat flux determination method is provided. Determination of the surface temperature field using liquid crystal thermography and corrections for radiative and conductive losses from the heat transfer surface is presented for the endwall surface of a 90° turning duct. The flow is fully turbulent in this square cross section duct. The solution of the surface heat flux distribution is also demonstrated for a rectangular surface that contains an array of discrete film cooling holes. The current method can easily be extended to any surface heater geometry that has arbitrary external or internal boundaries.

Original language | English (US) |
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Title of host publication | Gas Turbine Heat Transfer-1993 |

Editors | Louis C. Chow, Ashley F. Emery |

Publisher | Publ by ASME |

Pages | 21-31 |

Number of pages | 11 |

Volume | 242 |

ISBN (Print) | 0791811557 |

State | Published - 1993 |

Event | The 29th National Heat Transfer Conference - Atlanta, GA, USA Duration: Aug 8 1993 → Aug 11 1993 |

### Other

Other | The 29th National Heat Transfer Conference |
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City | Atlanta, GA, USA |

Period | 8/8/93 → 8/11/93 |

## All Science Journal Classification (ASJC) codes

- Fluid Flow and Transfer Processes
- Mechanical Engineering