COBEM99

SR27 Transferência de Calor e Massa

Title:

ANALYSIS OF THERMAL EFFICIENCY OF POROUS PLATE COOLING WITH AIR BLOWING

Summary :

AABSTRACT. IN THIS WORK, IT IS MADE THE STUDY OF THE EFFICIENCY OF POROUS FLAT PLATE COOLING BY INJECTION OF AIR. THE PLATE HAS POROSITY EQUAL TO 0,3 AND DIMENSIONS 0.6M X0.3MX0.003M. THE FLUID OF THE MAIN FLOW OVER THE FLAT PLATE IS HOT AIR. THE REYNOLDS NUMBER IN THE BORDER OF ATTACK OF THE POROUS WALL IS ALWAYS EQUAL OR GREATER THAN 250.000. THE SIMULATION RESULTS WERE OBTAINED USING BOTH THE MODELS OF THERMAL EQUILIBRIUM AND THERMAL NON-EQUILIBRIUM BETWEEN THE SOLID AND THE FLUID INSIDE THE POROUS WALL. THE NUMERICAL RESULTS HAVE SHOWN THAT THERMAL EQUILIBRIUM CONDITION MAY BE USED, WITHOUT CONSIDERABLE ERROR GENERATION, WHEN THE VALUES OF THE HEAT TRANSFER COEFFICIENT IN THE POROUS MEDIA ARE GREATER THAN MINIMUM VALUES PREVIOUSLY ESTABLISHED FOR EACH INJECTION TAX. THE RESULTS HAVE ALSO SHOWN THAT THERMAL RADIATION EFFECTS CAN DECREASE THE EFFICIENCY OF THE COOLING PROCESS IN UP TO 20% IN RELATION TO THE PROCESS IN ABSENCE OF THERMAL RADIATION. FURTHERMORE, THE THEORETICAL RESULTS THAT WERE OBTAINED WITH THE MATHEMATICAL MODEL ADOPTED IN THIS WORK HAVE SHOWN THAT THE THICKNESS OF THE POROUS PLATE DOESN T MODIFY THE EFFICIENCY OF THE COOLING PROCESS. KEY WORDS: TRANSPIRATION, POROUS WALL, COOLING, INJECTION

Author :

França, Geraldo Augusto Campolina
Lallemand, André 0
Mendonça Neves, Rita Célia Maciel

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