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THERMO 4

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  Procedure General Start-Up Procedures 1.   The main switch was ensured to be in off position. 2.   The power regulator knobs were fully turned anti-clockwise to set the power regulator to minimum. 3.   Valves V1 and V6 were checked to ensure it were closed. 4.   The chamber was filled with distilled water until the water level stays between the heaters and baffles plate. The heater was making sure to be fully immersed in the water throughout the experiment. Valve V4 was opened; water could be filled into the chamber through the drain. Then , closed the vent valve, v4 5.   Water flow rate to the condenser was adjusted by controlling the control valve according to the experimental procedure. 6.   Main switch and heater switch was turned on. The heater power was set by rotating the power regulator clockwise to increase heating power 7.   The water temperature reading was observed and it should increase when the water starts to increase. 8.   Water was heated up to boiling point untilled the pressure has reached 1.02 to 1.10 bar. Valve V1 was open immediately and followed y valve V5 for 1 minute in order for vacuum out air inside the condenser. 9.   The system let to be stabilized. Then all the relevant measurements for experimental purposes was recorded and adjusted if required. General Shutdown Procedure 1.   The voltage control knob was turned to 0 volt position by turning it fully anti-clockwise. 2.   Cooling water was allowed to flow for at least 5 minutes through the condensers to cool them down. 3.   The main switch and power system was switch off then the power cable was unplug 4.   The water supply was closed and cooling water connection was disconnected if necessary. 5.   The water inside the chamber was discharged using discharge valve.  Experiment 1: Demonstration of Filmwise and Dropwise Condensation 1.   The basic procedure that has been written in Section 6.1 was followed. The equipment was making sure to be connected to the service unit. Experiment 2: The Filmwise Heat Flux and Surface Heat Transfer Coefficient Determination at Constant Pressure 1.   Cooling water was circulated through the filmwise condenser starting the experiment with minimum value of 0.1LPM. 2.   The heater power was adjusted in order to obtain the desired pressure at 1.01 bars. 3.   When the condition has been stabilized, the steam (T sat ) and surface temperature (T surf  ), T in  (T1) and T out  (T2) also flow rate was recorded. Experiment 3: The Dropwise Heat Flux and Surface Heat Transfer Coefficient Determination At Constant Constant Pressure 1.   Cooling water was circulated through the dropwise condenser starting the experiment with minimum value of 0.4LPM. 2.   The heater power was adjusted in order to obtain desired pressure at 1.01 bar. 3.   When the condition has been stabilized, the steam (T sat ) and surface temperature (T surf  ), T in  (T1) and T out  (T2) also flow rate was recorded. Experiment 4: The Effect of Air inside Chamber 1.   Cooling water was circulated through the filmwise condenser at the highest flow rate until the pressure was reduced to below 1 bar. 2.   The discharged valve was opened to let air to enter the chamber. (Increase of 0.01% bar indicates 1% air is injected). 3.   The water flow rate to the condenser was regulated starting with a minimum value of 0.4LPM. 4.   The heater power was adjusted to obtain the desired pressure at 1.01 bar. 5.   When the condition has been stabilized, the steam (T sat ) and surface temperature (T surf  ), T in  (T1) and T out  (T2) also flow rate was recorded. 6.   Step 1-6 was repeated for dropwise condensation.  RECOMMENDATION 1)   Understand the procedure before starting experiment. Consultation as needed. 2)   Make sure tap water is always supply to the unit. 3)   Avoid error in taking readings and make sure eyes of observer are parallel to the meniscus 4)   Make sure the valve are close tightly when the film condensation equipment is turn off. 5)   Make sure all the valve close at the beginning of the experiment 6)   Allow the cooling water to flow at the end of the experiment before the equipment is shut down to avoid the cracking of cylindrical tube. 7)   If water level of the water level falls below the heater element, do not operate this unit as this will  permanently damage the heater. 8)   Cool down the equipment before draining the water inside the glass vessel so that the heater will not be overheated.  REFERENCES 1)   Aksan, S. N. and Rose, J. W. (1973). Dropwise condensation — the effect of thermal properties of the condenser material. Int. J. Heat Mass Transfer, 16, 461-467. 2)   Blackman, L. C. F., Dewar, M. S. J. and Hampson, H. (1957). Compounds for promoting dropwise condensation of steam. J. Appl. Chem., 7, 160-171. Date of search: 31/10/2014    http://www.freepatentsonline.com/5048600.html     http://www.p-a-hilton.co.uk/English/Products/Heat_Transfer/heat_transfer.html     http://wins.engr.wisc.edu/teaching/mpfBook/node9.html Date of search: 1/11/2014    http://www.focus-science.com/pahilton-heattransfer-h910.html     http://www.springerlink.com/content/46322536602154p1/     http://www.scribd.com/doc/22992765/Dropwise-and-Fimwise-Condensation-Lab-Report     http://www.husni.net/Labs/Files/HeatTransfer/Exp6.pdf       http://www.springerlink.com/content/u2882206203n3788/

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Jul 23, 2017
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