Vocabulary

heat transfer перенос тепла

solid boundary надійний кордон

vapour, steam пара

absorb всотувати

waves хвилі

sink желоб

heat exchanger теплообмінник

shell, casing кожух

handle liquid працювати з рідиною

bundle пучок

tube handle важіль труби

annulus кільце, зазор, зубчасте колесо

із внутрішнім зачепленням

tube / pipe sheet полотно труби

2. State whether the following statements are true or false and

comment on them using the introductory and connective words.

1. Only two mechanisms of heat transfer have already been established.

2. The transfer of heat by a mixing process is usually referred to as conduction. 3. Radiation is the transfer of heat by emission and absorption of energy without physical contact. 4. Radiation may occur independently of the other two mechanisms of heat transfer. 5. The vapor-side resistance depends upon the tempera­ture. 6. Materials of construction may vary, depending upon the fluids velosity. 7. Large heat-transfer surface can be achieved in double-pipe heat exchanger.

3. Translate and answer the following questions.

1. Які три види переносу тепла існують? 2. Чим радіація відрізняється від конвекції та конвенції? 3. Що спільнe мають між собою всі теплообмінники? 4. Що відображує коефіціент переносу тепла? 5. Які бувають види теплообмінників?

4. Find in the text the equivalents of the Ukrainian words and expressions:

eлектромагнітні хвилі, залежати від, джерело тепла, коефіціент переносy тепла, вираховувати коефіціент плівки, був запропонований, конструкція може бути різною, конденсаційна пара, заснований на, дорівнює сумі, опір конденсату, ведуча сила, відповідна температура, рідина рухається через, довжина, разом з потоком, відносно висока швидкість, нагрівач, охолоджувач, на низькій швидкості, розподіляється в трубах, паралельним потоком, витікає з труб, покидає пристрій, кожух.

5. Fill in the gaps.

emission, countercurrently, common, pipes, resistance, wave, cocurrently, exchanger, vapor, establish, simultaneously, transfer.

Two mechanisms of heat ____have already been established: It has been ____ that convection and conduction can occur simultaneously or individually. Radiatin occurs by ____ and absorption of energy without physical contact. Radiation depends upon electro­magnetic ____ as a means for transferring thermal energy from a hot source to a low-temperature sink. Radiation may occur ____ with, or independent of, the other two mechanisms of transfer. The one characteristic ____ to most heat exchangers is the transfer of heat from a hot phase to a cold phase with the two phases being separated by a solid boundary. A method of calculating film coefficients was proposed by Wilson for condensing ____. It is based on the overall ____. The double-pipe heat ____ is essentially two concentric ____. One fluid flowing through the center pipe while the other fluid moves ____ or ____in the annular space.

6. Match the notions and their definitions.

1) conduction, convection, heat-transfer cofficient, evaporation, radiation.

2) the operation of concentrating a solution by boiling away the solvent; the transfer of heat by a mixing process; the transfer of heat by molecular action; the transfer of heat by emission and absorption of energy without physical contact; a method of calculating film coefficient.

7. Define the words with the same root and use them in situations.

exchange – exchanger, solvent – solution – dissolve – solubility – soluble, vapour – evaporate – evaporation – evaporator.

8. Group the synonyms.

tube, raise, thermal energy transfer, heat transfer, place, casing,

enclose, device, unit, decrease, annulus,tramsmission, radiation, drop,

emission, solute, mix, tank, transmission, abrasive, shell, vessel, fall,

suspension, agitate, damaging, increase.

9. Transform the sentences using the Conditional Mood.

1. An appreciable heat-transfer surface is required, so banks of sections are frequently used. 2. The required area is too large, so a double-pipe exchanger is not recommended. 3. The centrifugal pumps have the disadvantages that their output is effected by changes in pressure on the delivery side and they are not suitable for viscous liquids. 4. Because of its positive-displacement characteristic, reciprocating pump is sometimes used for metering fluids. 5. Liquids containing abrasive solids should not be pumped with a reciprocating pump because of damage to the machined surfaces.

6. Liquid enters the cylinder through a check valve which is opened by an external pressure acting on the fluid. 7. The flow of the fluid through the inlet valves follows the piston movement backward through the cylinder on its inlet stroke. 8. When the piston moves forward, the inlet valve closes, and a second valve is forced open to discharge the liquid. 9.The piston must have a close fit with the cylinder walls in order to minimize liquid slip past the piston. 10. If the piston carries with it its own packing, it is called