Heal pipes

Wilkins, C., NPSH and Pump Selection Two Practical Examples, Healing, Piping and Air Conditioning, October 1988. 

AMCA Special Supplement, Healing Piping and Air Conditioning, Air Movement and Control Association, Inc., Feb. (1989), Air Movement and Control Association International, Inc. 

I0-66C A heal pipe with water as the working fluid is said to have an effective thermal conductivity of 100,000 V/m °C, which is more than 100,000 limes the conductivity of water. How can this happen ... 

C What happens when the wick of a heal pipe is too coarse or loo fine ... 

C Does the orientation of a heal pipe affect its performance Does it matter if the evaporator end of the heal pipe is up or down Explain. 

Reactors Process Towers Marine Veasela Piping Sysloms Heal Exchangers Tanks Unknown Process Drums Miscellaneous Heaiers-Boiiers... 

Data Base Development and Equipment Chemical Process, About 250 component failure rates and 95% Pumps, valves, pipe, motors, diesels, heal 51. 

One of the simplest and cheapest types of heat exchanger is the concentric pipe arrangement known as the double-pipe heat exchanger. Such equipment can be made up from standard fittings and is useful where only a small heal transfer area is required. Several units can be connected in series to extend the capacity. ... 

The pipe is then lagged with a 50 mm thickness of lagging of thermal conductivity 0.1 W/m K. If the outside heat transfer coefficient is given by the same equation as for the bare pipe, by what factor is the heal loss reduced ... 

An opposite eflect of emitlance occurs when an attempt is made to use aluminum jackets on very cold (cryogenic) piping. In this case, heal reaching the surface from surroundings is reflected away so that the metal surface becomes so cold thal it will condense and freeze moisture from the air. To overcome this surface condensation and freezing hy use of thicker thermal insulation on the lines would require a very great increase in thickness over that needed if the jacket had heen made of a heat-absorbing material that would keep the surface above the dew point. 

Fig. 2. Pipe insulauon over pipe and heal tracer line, v11h and without high-conducianee cement...

The heal transfer piping system is not simple. There were three reactors and the heat transfer system was used for both heating and C(xiling the reactor. The circulating fluid heats the reactor to several hundred degrees Fahrenheit to start the reaction. Once the ery exothermic reaction is underway, the circulating heat fluid removes heat from this reactor. (.See Figure 7-1.)... 

Z-Xl Water flows through a pipe at an average temperature of VO C. The inner and outer radii of the pipe are rf = 6 cm and rj = 6.5 cm. respectively. The outer surface of the pipe is wrapped with a thin electric heater that consumes 300 W pet m length of the pipe. The exposed surface of the heater is heavily insulated so that the entire heal generated in the heater is transferred to the pipe. Heat is transferred from the inner surface of the pipe to the water by convection with a heat transfer coefficient of h = 85 W/m K. Assuming constant thermal conductivity and one-dimensionat heat transfer, express the mathematical formulation (the differential equation and the boundary conditions) of the heal conduction in the pipe during steady operation. Do not solve. 

In steady operation, there is no change in the temperature of the pipe with time at any point. Therefore, the rate of heat transfer into the pipe must be equal to the rate of beat transfer out of it. In other words, heal transfer through tlie pipe must be constant, t cond.cyi constant. 

Chilled water enters a thin-shelled 5-cni-diameter, l50-m-long pipe at TC at a rate of 0,98 kg/s and leaves at 8°C. The pipe is exposed to ambient air at 30°C with a heal transfer co efficient of 9 W/m °C. If the pipe is to be insulated with glass wool insulation (k = 0.05 W/m °C) in order to decrease the temperature rise of water to 0.25°C, determine the required thickness of the insulation. 

Tfe A 50-m-long section of a steam pipe whose outer Wy diameter is 10 cm passes through an open space at IS C. The average temperature of the outer surface of the pipe is measured to be 150°C. If (he combined heal transfer coefficient on the outer surface of the pipe is 20 W/m C, determine (a) the rate of heat loss from the steam pipe (b) the... 

C A pipe is insulated to reduce the heal loss from it. However, measurements indicate that the rate of heat loss has increased instead of decreasing. Can the measuremeots be right ... 

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