INSTRUCTION: This paper consists of SIX (6) structured questions. Answer FOUR questions only.

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1 SULI JJ07: HERMODYNAMICS INSRUCION: is paper consists of SIX (6) structured questions. Answer FOUR questions only. ARAHAN: Kertas ini mengandungi ENAM (6) soalan berstruktur. Jawab EMPA (4) soalan saaja. UESION SOALAN CLO C (a) Convert te following units: ukarkan unit berikut: i. 5 MN/cm to GN/m 5 MN/cm kepada GN/m ii..3 g/mm 3 to kg/m 3.3 g/mm 3 kepada kg/m 3 iii. 55 mg/liter to kg/m 3 55 mg/liter kepada kg/m 3 [6 marks] [ 6 marka] SULI

2 SULI JJ07: HERMODYNAMICS CLO C (b) Explain te following: Berikan definisi berikut: i. System Sistem ii. Boundary Sempadan iii. Surrounding Sekeliling iv. Process Proses [8 marks] [8 marka] CLO C (c) Explain te Zerot Law of ermodynamics erangkan Hukum Zerot ermodinamik. [4 marks] [4 marka] CLO (d) Sketc te Zerot Law of ermodynamics diagram for (c) Lakarkan gambaraja Hukum Sifar ermodinamik untuk (c) [7 marks] [7 marka] 3 SULI

3 SULI JJ07: HERMODYNAMICS UESION SOALAN CLO C a) Based on figure, name te pases for te H O Berdasarkan raja, label nama fasa bagi H O P ( 6 ) ( ) ( 4 ) ( 5 ) ( ) ( 3) = const. = const. > Figure / Raja v [6 marks] [6 marka] CLO b) A wet steam at 4 bar and dryness fraction of 0.8. Calculate:- i) specific volume ii) specific entalpy and iii) specific internal energy Diberi stim basa pada 4 bar dan pecaan kekeringan 0.8. Kirakan:- i) isipadu tentu ii) iii) entalpi tentu dan tenaga dalam tentu [7 marks] [7 marka] 4 SULI

4 SULI JJ07: HERMODYNAMICS CLO c) Steam at 0 bar as a specific volume of.677 x 0 - m 3 /kg. Find te value of : i) temperature, ii) degree of supereat, iii) specific entalpy and iv) specific internal energy. Stim pada 0 bar mempunyai isipadu tentu.677 x 0 - i) suu, ii) darja panas lampau,, iii) entalpi tentu, iv) tenaga dalam tentu. m 3 /kg. Cari nilai: [7 marks] [7 marka] CLO d) Calculate te mass of air in a room wit te following dimensions: 4m x 5m x 6m and at 00 kpa and 5 C. Kira jisim bagi udara di dalam sebua bilik yang berukuran 4m x 5m x 6m pada 00 kpa dan 5 o C [5 marks] [5 marka] 5 SULI

5 SULI JJ07: HERMODYNAMICS UESION 3 SOALAN 3 CLO C (a) Define te following terms: erangkan istila-istila berikut i. eat Haba [ marks] [ marka] ii. specific eat aba tentu [ marks] [ marka] CLO (b) Calculate te energy differences for te system below. Kirakan perubaan tenaga dalam bagi sistem dibawa. = 7kJ sistem = 60kJ =5kJ = 80kJ [4 marks] [4 marka] 6 SULI

6 SULI JJ07: HERMODYNAMICS CLO (c) A quantity of gas as a pressure of 3.5 bar wen te volume and te temperature is 0.03m 3 and 35 o C respectively. Specific gas constant is 0.9 kj/kgk. Calculate te mass of gas. Satu Kuantiti gas mempunyai tekanan 3.5bar apabila isipadu dan suunya masing-masing 0.03m 3 dan 3C. Pemalar gas adala 0.9kJ/kgK. Kirakan jisim gas tersebut. [5 marks] [5 marka] CLO C4 (d) A closed system containing kg of air undergoes an isotermal process from 600kPa at 00 o C to 80kPa. Determine te initial volume of tis system, te work done, and te eat transfer during tis process. Satu sistem tertutup mengandungi kg udara melalui proses suu malar dari 600kPa pada suu 00 o C kepada 80kPa. Kirakan isipadu awal gas, kerja terlaku dan aba yang berpinda semasa proses berlaku. [ marks] [ marka] 7 SULI

7 SULI JJ07: HERMODYNAMICS UESION 4 SOALAN 4 CLO C (a) State HREE (3) devices tat use te principal of flow process Nyatakan IGA (3) alat yang menggunakan prinsip proses alir [3 marks] [3 marka] CLO C (b) Differentiate between flow process and non-flow process Bezakan di antara proses alir dan proses tak alir [4 marks] [4 marka] 8 SULI

8 SULI JJ07: HERMODYNAMICS CLO C4 (c) Steam flows steadily into a turbine at 5400 kg/ and produces 500 k of power. Properties of steam for inlet and outlet part of te turbine are sown in te table below. If te potential energy can be neglected, determine: i. e eat wic is transferred to surrounding ii. te area for te outlet vessel Stim mengalir secara mantap memasuki sebua turbin dengan kadar 5400 kg/jam dan mengasilkan kuasa keluaran sebanyak 500 k. Keadaan stim pada baagian masuk dan keluar dari turbin adala seperti di jadual 4 Jika tenaga keupayaan diabaikan : i. Kira nilai aba yang dipindakan ke persekitaran ii. entukan luas baagian keluaran Inlet masukan Outlet keluaran Velocity, C Halaju aliran, C 330 m/s 9 m/s Pressure, P ekanan, P 0 bar.4 bar Internal Energy, U enaga dalaman, U 3770 kj/kg 550 kj/kg Specific volume, υ Isipadu tentu, υ 0.65 m 3 /kg.8 m 3 /kg able 4 / Jadual 4 [8 marks] [8 marka] 9 SULI

9 SULI JJ07: HERMODYNAMICS UESION 5 SOALAN 5 CLO C (a) Give O () differences between te First law of ermodynamics and te Second Law of ermodynamics. Berikan DUA () perbezaaan di antara Hukum ermodinamik Pertama dan Hukum ermodinamik Kedua. [8 marks] [8 marka] CLO (b) A steam boiler receives 460 kj/min of eat and produces 5 k of power. Determine te eat tat is absorbed by te river and te termal efficiency. Dandang stim menerima sebanyak 460 kj/min tenaga aba dan mengasilkan kuasa sebanyak 5 k. entukan tenaga aba yang diserap ole sungai dan kecekapan terma. [7 marks] [7 marka] CLO C4 (c) e reversed Carnot eat engine receives eat at temperature of 0C and rejects te eat at temperature of 3C wit eat transfer of 00 k. Determine te power required in kj/r. Enjin aba Carnot yang bertentangan menerima aba pada suu 0C dan memindakan aba sebanyak 00 k pada suu 3C. entukan kuasa yang diperlukan dalam kj/r. [0 marks] [0 marka] 0 SULI

10 SULI JJ07: HERMODYNAMICS UESION 6 SOALAN 6 CLO C (a) Define ONE () caracteristic of eat engines and give ONE () example of eat engine. Nyatakan SAU () ciri-ciri enjin aba dan berikan SAU () conto enjin aba. [3 marks] [3 marka] CLO C (b) Differentiate te function of te eat pump and refrigerator. Bezakan fungsi di antara pam aba dan peti sejuk. [4 marks] [4 marka] CLO (c) A steam at pressure of 3 bar and entalpy of 85 kj/kg is expanded isobarically to temperature 00C. Determine te entropy cange. Stim pada tekanan 3 bar dan entalpi sebanyak 85 kj/kg dikembangkan secara setekanan kepada suu 00C. entukan perubaan entropi. [6 marks] [6 marka] SULI

11 SULI JJ07: HERMODYNAMICS CLO C4 (d) A ouse air conditioner maintained eat at 00 kj/s and temperature of 7C and rejected te eat at 555 kj/s. Determine te power input and coefficient of performance. If te ouse air conditioner temperature is reduced to C wile maintaining te temperature at te sink, determine te new coefficient of performance. Penyaman udara ruma mengekalkan aba sebanyak 00 kj/s pada suu C dan mengeluarkan aba sebanyak 555 kj/s. tentukan kuasa yang dibekalkan dan pekali kecekapan.jika penyaman udara ruma menurunkan suu kepada C sementara mengekalkan suu pada sinki, tentukan pekali kecekapan yang baru. [ marks] [ marka] SOALAN AMA SULI

12 SULI JJ07: HERMODYNAMICS Rumus JJ07. FIRS LA OF HERMODYNAMICS Σ = Σ = U U. FLO PROCESS m = ρva = ρv (kg/s) = CA m V C C m Z Z g 3. PROPERIES OF PURE SUBSANCE Steam xs fg v = xv g = f + x fg u = u f + x(u g u f ) s = s f + Ideal Gas PV = mr R = R o R = C p - C v γ = C p M C v Non-Flow Process. Isotermal Process ( PV = C ) U U = 0 = V PV P V PV ln P 3 SULI

13 SULI JJ07: HERMODYNAMICS 4 SULI ln V V ln P P PV. Adiabatic Process ( PV γ = C) U U = mc v ( - ) ) ( mr P V PV = 0 V V P P 3. Politropic Process ( PV n = C ) U - U = mc v ( - ) PV P V n mr n n x n n n V V P P 4. Isobaric Process U -U = mc v ( ) = P(V - V )= mr ( ) = mc p ( - ) 5. Isometric Process U U = mc v ( ) = 0 = U -U =mc v ( - ) 4. SECOND LA OF HERMODYNAMICS Heat Engine H L H out net t, Refrigerator /, L H L H L rev R COP

14 SULI JJ07: HERMODYNAMICS Heat Pump H COPHP, rev H L / L H Entropy 5. GAS POER CYCLES r Vmax VBDC V v V V V v min DC MEP V net disp net in out t in in out in Otto Cycle t, were k c k r Diesel Cycle k rc t, k r k( rc ) v3 were rc (cutoff ratio) v p / c v 5 SULI

15 SULI JJ07: HERMODYNAMICS 6 SULI Brayton Cycle in c t in net t 4 3 r turb comp bw k k p t r )/ (

EMH 211 Thermodynamics [Termodinamik]

UNIVERSITI SAINS MALAYSIA First Semester Examination Academic Session 2015/2016 December 2015 / January 2016 EMH 211 Thermodynamics [Termodinamik] Duration : 3 hours Masa : 3 jam Please check that this