報告書番号

W97002

タイトル（和文）

三次元モデルによるＭＣＦＣスタック特性解析種々のガス流れ方式の性能比較及び放熱量の影響評価

タイトル（英文）

ANALYSES OF MCFC STACK PERFORMANCE USING 3D NUMERICAL MODELS -COMPARISON OF STACK PERFORMANCE FOR VARIOUS GAS FLOW TYPES AND ANALYSES OF MEAT LOSS EFFECTS ON STACK PERFORMANCE-

概要 （図表や脚注は「報告書全文」に掲載しております）

ＭＣＦＣスタック３次元温度分布解析モデルを作成し，１０ｋＷ級スタックのセル電圧及び温度分布実測値との比較によりモデルの有効性を確認した。本モデルを用い，種々のガス流れ方式スタックの性能，温度分布ならびにスタック冷却動力等を比較した結果，スタックの有効出力（ＭＣＦＣ出力から冷却に必要な動力を差し引いた出力）が最も高いこと及びスタック最高温度の監視が比較的容易なことから，外部改質型プラントの場合，セル平面内のガス流配を均一と仮定すると並行流型スタックが最も有利であることが分かった。また，スタックからの放熱がセル性能及び温度分布に与える影響について，スタック上下面及びスタック側面に分けて検討を行った結果，上下面からの放熱の影響が大きく，特に１．７～２ｋＷ／ｍ２以上の放熱量となる場合上下端部付近で発電下限温度を下回る可能性があるため，スタック上下での有効な断熱構造の採用が重要となることが分かった。

概要 （英文）

A 3D MODEL OF THE MCFC STACK THAT CAN CALCULATE TEMPERATURE PROFILES AND STACK PERFORMANCE HAS BEEN CONSTRUCTED. THIS MODEL CAN ANALYZE VARIOUS GAS-FLOW-TYPE STACK PERFORMANCES. TO CONFIRM THE EFFECTIVENESS OF THIS MODEL,CALCULATED TEMPERATURE PROFILES AND STACK PERFORMANCES WERE COMPARED WITH EXPERIMENTAL DATA. CALCULATED TEMPERATURE PROFILES AND CELL PERFORMANCES SHOWED GOOD AGREEMENT WITH EXPERIMENTAL DATA FOR A 10-KW CLASS STACK. USING THIS MODEL, WE ANALYZED THE TEMPERATURE PROFILE, STACK PERFORMANCE AND COOLING GAS FLOW RATE FOR THREE TYPES OF PARALLEL FLOW AND TWO TYPES OF CROSS FLOW. IT IS IMPORTANT TO CALCULATE THE TEMPERATURE PROFILES AND STACK PERFORMANCES WHEN THE CATHODE INLET TEMPERATURE IS 580DEGREE AND THE OUTLET TEMPERATURE IS 680DEGREE. FROM THE RESULTS, THE CO-FLOW TYPE STACK IS THE MOST SUITABLE GAS-FLOW TYPE FOR THE EXTERNAL-REFORMING TYPE, BECAUSE THE NET OUTPUTPOWER (MCFC OUTPUT POWER MINUS COOLING POWER BY CATHODE RECYCLING BLOWER) SHOWS THE HIGHEST PERFORMANCE. FURTHERMORE, THE MAXIMUM TEMPERATUREOF THE STACK SHOWED ALMOST THE SAME TEMPERATURE AS THE CATHODE OUTLET TEMPERATURE IN THE CO-FLOW TYPE STACK, SO OBSERVATION OF THE MAXIMUM TEMPERATURE IS EASIER THAN OTHER GAS-FLOW TYPES OF STACK. USING THIS MODEL, WE ANALYZED THE HEAT-LOSS EFFECT FOR THE STACK TEMPERATURE PROFILES AND STACK PERFORMANCES. THE HEAT LOSS FROM THE SIDE SURFACE OF THE STACK AND FROM THE TOP AND BOTTOM SURFACE WERE CONSIDERED. FROM THE RESULTS, THE HEAT LOSS FROM THE TOP AND BOTTOM SURFACE SERIOUSLY INFLUENCES THE TEMPERATURE PROFILE AND STACK PERFORMANCE. WHEN THE HEAT LOSS EXCEEDS1.7 TO 2.0 KW/M2, THE TEMPERATURE OF THE END CELL FULLS BELAW THE GENERATABLE TEMPERATURE. ON THE OTHER HAND, THE HEAT-LOSS EFFECT FROM THE SIDE SURFACE OF THE STACK HAD LITTLE INFLUENCE ON THE TEMPERATURE PROFILE WHEN THE GAS FLOW CHANNEL WIDTH IS LARGE. EVEN AT A SHORT GAS FLOW CHANNEL WIDTH, THE STACK SHOWED HIGH PERFORMANCE. FROM THESE RESULTS, THEHEAT INSULATING METHOD FOR THE TOP AND

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