SU1064113A1 - Heat pipe operation process - Google Patents

Abstract

1. METHOD OF WORK OF A HEAT PIPE by partial evaporation of a heat transfer medium in an evaporation zone, separation of steam from a liquid, vapor transported under the action of a pressure differential to a condensation zone, condensation of vapor, mixing condensate with a separated liquid, transporting a heat transfer fluid down by gravity and viscous forces in the zone of evaporation and its partial cooling during transportation, characterized in that, in order to increase thermodynamic efficiency in the transfer of heat from top to bottom, as a coolant use a mixture of liquids that produce heat when mixed, and before mixing the condensate and the separated liquid, they are transported down separately, and the condensation is dried at the initial temperature corresponding to 1.-

Description

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The invention relates to power engineering, in particular to heat pipes - tag exchangers with an intermediate heat carrier.

A known method of operating a heat pipe by evaporating a heat transfer fluid when heat is supplied, transporting vapor to the condensation zone of the body under the action of a vapor pressure differential, condensing vapor during heat removal and transporting liquid to the evaporation zone of the body by a capillary pump 1.

The disadvantage of this method is the inability to transfer heat for considerable distances when the pipe is operated against gravity.

There is also known a method of operating a heat pipe by evaporating a heat transfer fluid in an evaporation zone, transporting vapor to a condensation zone under the action of a pressure differential, condensing vapor in a condensation zone, and transporting a heat transfer fluid to an evaporation zone due to gravity or a pressure differential created by valves 2

The disadvantage of this method is the pulsed mode of operation with heat transfer from top to bottom.

A known method of operating a heat pipe is by partially evaporating the coolant in the evaporation zone, separating steam from the liquid, transporting the vapor under the action of a pressure differential to the condensation zone, condensing the vapor, displacing the condensate with the separated liquid, transporting the heat carrier down under the force of gravity and viscous forces in evaporation zone and partial cooling during transport 3.

The disadvantage of this method is the low thermodynamic efficiency in heat transfer from top to bottom.

The purpose of the invention is to increase the thermodynamic efficiency of heat transfer from top to bottom.

The goal is achieved by the fact that according to the method of operation of a heat pipe by partial evaporation of the coolant in the evaporation zone, separation of steam from liquid, transportation of vapors under the action of pressure drop to the condensation zone, condensation of vapors, displacement of condensate with the separated liquid, transportation of the coolant down under the action of forces tin and viscous forces in the evaporation zone and its partial cooling during transportation, a mixture of liquids that produce heat when displaced is used as the coolant , Wherein prior to the displacement of condensate and the separated liquid are conveyed down separately, and condensation is carried out at an initial temperature corresponding to the condition PC- {1- C) "" tyji, GDR koydensatsii initial temperature;

i is the temperature corresponding to the critical pressure of the condensate;

f beats the temperature corresponding to a given specific heat of condensation of coolant vapors. As a coolant can be used ammonia water solution with a mass fraction of ammonia 0.20-0.80.

The drawing shows a heat pipe for implementing the method.

The heat pipe contains a hermetic body, partially filled with a liquid heat carrier, containing a condensation zone 1, an additional condensate line 2, a V-shaped condensate line including a cooling zone 3, a liquid heat exchanger 4 and an initial section 5, an evaporation zone 6 and a liquid separator 7. An additional condensate line 2 connects the liquid cavity of the condensation zone 1 to the bottom of the V-shaped condensate line, located up to the cooling zone 3. The level of the liquid coolant is within the separator 7 of the liquid, and the V-shaped condensate line, with the exception of the initial section 5, is located under the evaporation zone 6. The condensation, cooling and evaporation zones have developed heat exchange surfaces.

Heat pipe works as follows.

0 When heat transfer Qf to the evaporation zone (at a temperature level of 20-150 ° C, exceeding the ambient temperature), the heat transfer medium is partially evaporated (with a ratio f equal to the ratio of the flow rate of the separated liquid to the steam flow rate

5 and f 0.5-l, 5 for the optimal variant with obtaining the maximum heat of mixing), separating the vapor from the liquid in the liquid separator 7, transporting the steam under the action of differential partial pressures to the condensation zone 1, where heat is diverted from the heat Q collecting the liquid in the lower part of the cavity of the condensation zone, transports condensate through condensate line 2 and mixes it with the separated liquid to the cooling zone 3 in the lower part of the v-shaped condensate line; heat Qo is removed from the cooling zone 3 (temperature whose ature level can be equal to the minimum temperature level of heat supply in the evaporation zone). The coolant, formed after displacement, transfers its heat to the separated liquid to return it to the cooling zone. Then the coolant is heated again, and so on.

The thermal coefficient of heat transfer down can be estimated as follows:

5g, .QO QO

 u Qo QrTT | f From this it follows that with. This condition can be ensured by lowering the heat of vaporization of the heat transfer medium, i.e., operating at condensation temperatures close to those corresponding to the critical condensate pressure Qo Gt / iH mixing + CdT-O1, where iH mixing kcal / kg is the heat of mixing;

Gf-Cooling coolant coolant.

Gt coolant flow. The optimal range of maximum condensation temperatures of a heat pipe is limited on the one hand by the temperature corresponding to the critical condensate pressure minus 1-5 ° C for possible fluctuations of parameters and temperature.

corresponding to the specified specific heat of condensation of heat carrier vapors (in a condenser), which is numerically equal to twice the heat of mixing of the condensate and the separated liquid.

Reducing the critical pressure of the coolant is provided by selecting the appropriate condensate and the separated liquid. In this case (; m case, the minimum condensation temperature should not be lower than the ambient temperature (5-10 ° C).

The economic effect obtained as a result of using the method of operating a heat pipe is achieved due to an increase in thermodynamic efficiency.

Claims (2)

1. METHOD OF OPERATION OF A HEAT PIPE by partial evaporation of a heat carrier in a zone of evaporation, separation of steam from a liquid, transportation of vapors under the influence of pressure difference in a condensation zone, condensation of vapors, mixing of condensate with separated liquid, transportation of a heat carrier down under the action of gravity and viscous forces into a zone partial evaporation and cooling it during transportation, characterized in ⁰ that, in order to improve thermodynamic efficiency in heat transfer from the top downward, as, coolant and polzujut mixture of liquids, produce heat when mixed, the condensate and the separated liquid are conveyed down separately and condensation before mixing is carried out at an initial temperature corresponding to the condition. . . [1 _k - (1-5 ⁰ C) M _nk <1 _U d> where ί «κ is the initial condensation temperature; 1 k temperature corresponding to the critical pressure of the condensate; (beats is the temperature corresponding to> a given specific heat of condensation of the coolant vapor. 2. The method according to π. 1, characterized in that as a heat carrier use a water-ammonia solution with a mass fraction of ammonia of 0.20-0.80 ,.