Section A
Q1.
(a) changes are negligible? How is it different from a closed stationary system? 8 Explain various methods to increase the power output of the IC engines with
(b) 8 same volumetric capacity. The inner and outer surfaces of a spherical container are maintained at |c| temperatures of T1 = 200 °C and T2 = 80 °C, respectively. The container is having the following dimensions : Inner radius = 8 \text cm, outer radius = 10 \text cm The thermal conductivity of the container material is 45 W/m-K. Obtain a general relation for the temperature distribution inside the container under steady conditions and also, determine the rate of heat loss from the container. 8 A Carnot refrigerator has working temperatures of -30 °C and 35 °C. If it
(d) operates with R12 as a working substance, calculate the work of isentropic compression and that of isentropic expansion. Also, calculate the refrigerating effect, heat rejected per kg of the refrigerant and COP of the cycle. 8 Thermodynamic properties of R12 Satura- Satura- Vapour Superheated Saturated Liquid and Vapour tion tion By 40 °C By 20 °C Temp. Pressure h h s s hf sg t ηg sf p vf vg (1)/((m3 / kg)) (kJ/kg) (kJ/kg) (kJ/ (kJ/kg) (kJ/ (kJ/kg) (kJ/ (kJ/kg) (kJ/ (\circC) (bar) kg-K) kg-K) kg-K) kg-K) 0.8178 0.7737 192 - 4 0.7274 180 - 8 0.66 0.2421 169.0 0 0 0.6417 -40 0.8120 0.7220 183.3 0.7681 195 - 1 171-9 0.0187 0.8069 0.67 0.1950 4 - 4 -35 197.8 0.8068 0.7631 174.2 0.0371 0.7171 185 - 8 1.0038 0.67 0.1595 8-9 -30 200-4 0.8021 0.7127 188.3 0.7586 176 - 5 0.0552 1.2368 0.68 0.1313 13-3 -25 0.7979 190.8 0.7546 203-1 0.7088 178 - 7 0.0731 1.5089 0.69 0.1089 17-8 -20 0.7942 0.7052 193.2 0.7510 205 - 7 22.3 1810 0.0906 0.0911 1.8256 0.69 -15 0.7909 195 - 7 0.7477 208-3 0.7020 183 - 2 0.1080 2.1912 0.70 0.0767 26.9 -10 210-9 0.7879 0.6991 198 - 1 0.7449 0.71 31 - 4 185-4 0.1251 0.0650 2.610 -5 0.7423 213.5 0.7853 0.6966 200-5 0.72 187 - 5 0.1420 3.086 0.0554 36-1 0 202 - 9 0.7401 216-1 0.7830 0.6942 0.72 189.7 0.1587 3.626 0.0475 40.7 5 218.6 0.7810 0.1752 0.6921 205 - 2 0.7381 0.0409 45.4 191 - 7 4.233 0.73 10 0.7792 0.6902 207.5 0.7363 221 - 2 0.0354 193.8 0.1915 4.914 0.74 50-1 15 0.7777 223 - 7 0.2078 0.6885 209.8 0.7348 0.75 0.0308 54.9 195-8 5.673 20 0.7334 226.1 0.7763 0.2239 0.6869 212.1 197 - 7 0.76 0.0269 59.7 6.516 25 0.7751 214-3 228 - 6 0.77 0.2399 0.6854 0.7321 7-450 0.0235 64.6 199.6 30 0.7310 231 - 0 0.7741 201 - 5 0.6839 216 - 4 0.79 0.0206 69.5 0.2559 8.477 35 0.7300 233-4 0.7732 0.6825 218.5 0.80 74 6 203-2 0.2718 9.607 0.0182 40 0.7724 0.6812 220.6 0.7291 235 - 7 0.81 0.0160 79.7 204.9 0.2877 10.843 45 0.3037 222.6 0.7282 238.0 0.7718 0.83 84.9 206 - 5 0.6797 0.0142 12.193 50 226 - 4 0.7265 242 - 4 0.7706 209.3 0.6777 95-7 0.3358 15.259 0.86 0.0111 60 230 - 2 246.2 0.7650 211-5 0.7240 0.90 0.0087 107 - 1 0.3686 0.6738 18.859 70 \overlinea JKLO–B–MCHE/61