熱力學(xué)第一定律thefirstlawofthermodynamics(參考版)
2024-07-31 00:36本頁面
【正文】 當(dāng)當(dāng)質(zhì)量為 的物質(zhì)離開系統(tǒng)時 ,系統(tǒng)的熵將減少 ) msS mf ?,msmmsmmsmsm4. Entropy Equation (熵方程 ) (1) Entropy balance of any system undergoing any process can be expressed as (任何系統(tǒng)經(jīng)過任何過程的熵平衡可表達(dá)為 ) (2) For closed system (對于閉口系統(tǒng) ) The entropy change of a closed system during a process is equal to the sum of the entropy transferred through the system boundary by heat transfer and the entropy generation within the system boundaries. (經(jīng)過一個過程 ,閉口系統(tǒng)的熵變等于通過邊界的熱量熵流與系統(tǒng)內(nèi)部的熵產(chǎn)之和 ) s y s te mg e noutin ssss ????12 ssssTqs y s te mg e nkk ??????For adiabatic closed system For any closed system and its surroundings s y s te ma d ia b a ticg e n ss ??g e ns u rs y s ssss ???????sursursur Tqs ??(2) For Open System (對于開口系統(tǒng) ) The entropy change of a Open system during a process consists of （經(jīng)過一個過程 ,開口系統(tǒng)的熵變由下列部分組成） A. the entropy transferred through the system boundary by heat transfer (通過邊界的熱量熵流 ) B. the entropy transfer into the system by mass flow (進(jìn)入系統(tǒng)的凈質(zhì)量熵流 ) C. the entropy generation within the system boundaries as the result of irreversibility. (系統(tǒng)內(nèi)部不可逆所導(dǎo)致的熵產(chǎn) ) s y s te mg e noutoutinin SSsmsmTQ ????? ??? For steadyflow system (對于穩(wěn)態(tài)穩(wěn)定流動系統(tǒng)） For single stream, adiabatic, steady flow （對于單股絕熱的穩(wěn)態(tài)穩(wěn)定流動系統(tǒng)） 0???? ??? g e noutin sssTqg e ninout sss ?? Significance of Entropy and its application (熵的意義及應(yīng)用 ) 1. Heat absorption and heat rejection during a reversible process can be calculated by resorting to Entropy. (可逆過程中的吸熱或放熱量可借助熵來計算） T d SQ re ?)(?放熱）絕熱吸熱(h eat r ej ec t 0,dS)( ad i ab at i c 0,dS)(h eat ab s o r b ,0???dS2. Entropy generation indicates the direction of process in isolated system. (熵產(chǎn)是孤立系統(tǒng)中過程進(jìn)行方向的標(biāo)志） ?????????)( p r o c e s s i m p o s s i b l e 0)( p r o c e s s r e v e r s i b l e 0)( p r o c e s s lei r r e v e r s i b 0不可能可逆過程不可逆過程g e ndSheat transfer across a finite temperature difference（溫差傳熱） Free or unrestrained expansion（自由膨脹） 3. Entropy is a measurement of the amount of thermal energy which can not be converted to work. (熵是熱量不可用能大小的量度） Generation indicates the amount of loss in energy which can be converted to work. (熵產(chǎn)是做功能力損失的量度） T s TH T0 s1 s2 heat transfer across a finite temperature difference（溫差傳熱） Friction Loss (摩擦損失） TL TH T s s1 s2 s3 TH TL T0 Q1 Q1 Q2 W T0 TH Wmax Q2 Q1 T0 Reading and Review (閱讀和復(fù)習(xí)） Introduction （簡介） ~ Statement of the Second Law of Thermodynamics （熱力學(xué)第二定律的表述）~ Carnot cycle and Carnot Theorem （卡諾循環(huán)與卡諾定律） ~P281 Entropy, The increase principle of Entropy and Entropy Equation （熵、熵增原理及熵方程） Significance of Entropy and its application (熵的意義及應(yīng)用 ) ~359 。換句話說，即孤立系統(tǒng)的熵不會減?。? Tqds ??0?isodS Why does not entropy of isolated system decrease? (為什么孤立系統(tǒng)的熵不會減少？） Only irreversibilities can lead to the increase in entropy of an isolated system.（不可逆性是導(dǎo)致孤立系統(tǒng)熵增大的唯一原因） Such as heat transfer across a finite temperature difference（溫差傳熱） friction（摩擦） Free or unrestrained expansion（自由膨脹） mixing of two fluids（液體的混合） electric resistance（電阻） inelastic deformation of solid（固體的塑性變形） chemical reactions（化學(xué)反應(yīng) ） generation and Entropy flow (熵產(chǎn)與熵流 ) (1) Entropy generation is caused by any irreversibility. ( 熵產(chǎn)是由不可逆因素引起的熵變 ) is
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