Food Engineering- I — DU B.Sc. (Hons.) Food Technology Previous Year Question Papers

flow rate of refrigerant, the compressor power requirement, and the C.O.P. Assume the unit operates under saturated conditions and the compressor efficiency is 80%. (8) 6. Explain the following with a well labeled diagram : (any three) (6×3=18) (a) Super critical fluid extraction (b) Basket centrifuge (c) Electrodialysis system (d) Shell and tube heat exchanger 7. (a) Derive the expressions for the following parameters with the help of a schematic diagram and Pressure- Enthalpy Diagram : (10) I. Refrigerating effect II. Work done by the compressor III. Coefficient of performance (COP) IV. Heat rejected in the condenser. (b) One face of a stainless-steel plate 2 cm thick is maintained at 120°C, and the other face is at 80°C. Assuming steady-state conditions, calculate the rate of heat transfer per unit area through the plate. The thermal conductivity of stainless steel is 17 (NEP-UGCF) Attempt five questions in all. All parts of the question should be attempted together. Conversion tables and chart is permitted. 1. Describe the following briefly : (Any Nine) (b) Unit operation (c) Thermal conductivity (d) Newton’s law of cooling (e) Filter aid (f) Overall heat transfer coefficient (h) Dimensional analysis (i) System of units (j) Steam Distillation 2. Differentiate between the following : (Any Three) (a) Hildebrandt and Bollman extraction (b) Spiral wound and hollow fibre membrane modules (c) Conduction and convection (d) Tubular and Disc bowl centrifuge 3. Write short notes on the following : (any three) (a) Fick’s law of diffusion (c) Frozen food storage (d) Radiation: a mode of heat transfer (e) VCR Cycle 4. (a) Develop calculations involving for designing a tubular heat exchanger under steady-state heat transfer conditions. (8) (b) Compute the freezing time for a spherical food product which is being frozen in an air-blast freezer. The initial product temperature is 8°C and the cold air -40°C. The product has a 6 cm diameter with density of 1000 kg/m 3, the initial freezing temperature is -1.5°C, the thermal conductivity of the frozen product is 1.2 W/(mK), and the latent heat of fusion is 250 kJ. (8) (c) Discuss the desirable properties of a refrigerant for a VCR System. (2) 5. (a) Describe the different types of heat transfer equipment used for food processing. (6) (b) Convert the following : (4) (ii) pressure value of 17.11 psig to kPa (c) A cold storage room is being maintained at 4°C using a vapor-compression refrigeration system that uses R-134a. The evaporator and condenser temperatures are -6 and 40°C, respectively. The refrigeration load is 25 tons. Calculate the mass