CN102735708B - Determination system and method for heat exchange coefficient of cooper pipe - Google Patents

Abstract

The present invention discloses a determination system for a heat exchange coefficient of a cooper pipe. The system comprises a cooper pipe inlet, a cooper pipe outlet, and a sleeve type test mechanism. The sleeve type test mechanism comprises an inner bush and an outer bush, wherein the inner bush is installed inside the outer bush, and a closed outer bush cavity is formed between the outer bush and the side wall of the inner bush, and is provided with an outer bush inlet and an outer bush outlet. The interior of the inner bush is provided for installing a cooper pipe requiring detection. A closed inner bush cavity is formed between the side wall of the cooper pipe requiring detection and the inner bush, and is provided with an inner bush inlet and an inner bush outlet. The outer bush inlet and the outer bush outlet of the outer bush cavity are connected with a steam generator to form a circulation circuit. The inner bush inlet is connected with the steam generator. The system and the method of the present invention have the following advantages that: it is ensured that the steam temperature is 100 DEG C when the steam enters double layers of the bushes from the steam generator; the outer bush can provide complete heat insulation for the inner bush; and the operation is simple, and the implementation is easy.

Description

A kind of mensuration system and method for copper tube heat exchange coefficient

Technical field

The present invention relates to a kind of metal tube Measured Results of Thermal Conductivity field, be especially applicable to the mensuration system and method for a kind of copper tube heat exchange coefficient of the metal tube that the coefficient of heat conductivity such as copper are strong.

Background technology

At present, the air-condition heat exchanger that China is used mainly contains the inner screw thread copper pipe that adopts different tube diameters.Inner screw thread copper pipe producer processes the inner screw thread copper pipe of different size according to the requirement of air-conditioning factory, for the inner screw thread copper pipe of different size, its heat transfer effect quality is judgement by rule of thumb only.For this problem, be necessary the copper tube heat exchange coefficient of different size to test, producer can transformation and optimization internal thread equipment like this, to produce efficient heat exchange copper tube, meets the demand of air-conditioning factory to inner screw thread copper pipe.

Summary of the invention

Technical matters to be solved by this invention is the deficiency existing for prior art, and the mensuration system of a kind of copper tube heat exchange coefficient that can simple and quick detection metal heat-exchange coefficient is provided.

Another object of the present invention is to provide a kind of assay method of copper tube heat exchange coefficient.

The present invention is achieved by the following technical solutions: a kind of mensuration system of copper tube heat exchange coefficient, comprise copper pipe import, copper pipe outlet and bushing type test mechanism, described copper pipe import and copper pipe outlet are installed on respectively the both sides of described bushing type test mechanism, described bushing type test mechanism comprises inner sleeve and outer sleeve, described inner sleeve is installed in described outer sleeve, between described outer sleeve and inner sleeve sidewall, form the overcoat cavity of sealing, described overcoat cavity is provided with outer sleeve import and outer sleeve outlet; Described inner sleeve is interior for copper pipe to be detected is installed, and between described copper pipe sidewall to be detected and inner sleeve, forms the inner sleeve cavity of sealing, and described inner sleeve cavity is provided with inner sleeve import and inner sleeve outlet; The outer sleeve import of described overcoat cavity and outer sleeve outlet are connected to form closed circuit with steam generator, and described inner sleeve import is connected with described steam generator.

Described inner sleeve outlet is connected with condensate collector.

Described copper pipe inflow point is provided with inflow point's thermometer and flowmeter, and described copper pipe exit is provided with exit thermometer.

Described outer tube lateral wall is enclosed with heat-insulation layer.

Described copper pipe inflow point is provided with water intaking valve.

Between described copper pipe import and copper pipe outlet, differential manometer is installed.

On described steam generator, be provided with steam side thermometer and pressure limiting valve.

In described bushing type test mechanism, pipeline is all enclosed with insulation material.

An assay method for copper tube heat exchange coefficient, is used the mensuration system of above-mentioned copper tube heat exchange coefficient, and its step comprises:

(1) by the length dimension requirement of the mensuration system inner sleeve type test mechanism of copper tube heat exchange coefficient, prepare copper pipe to be detected, and copper pipe to be detected is arranged between the copper pipe import and copper pipe outlet of inner sleeve of bushing type test mechanism;

(2) open water intaking valve, open steam generator, open steam side valve;

(3) controlling steam side temperature is 100 degree, records discharge, inflow point's temperature, exit temperature after waiting for a period of time;

(4) steam off generator, steam side valve, water intaking valve successively;

(5) according to following heat balance equation, utilize discharge, inlet temperature, outlet temperature, the copper pipe size to be detected measured, calculate the coefficient of heat transfer of copper pipe:

Heat balance equation is:

Mean temperature difference (MTD) Δ t _m:

${\mathrm{\Δt}}_m=\frac{t_o-t_{\mathrm{in}}}{\ln \left(\frac{t_s-t_{\mathrm{in}}}{t_s-t_o}\right)}---\left(1\right)$

In formula, t _othe outlet temperature of water in pipe, t _inthe inlet temperature of water in pipe, t _sit is the temperature of saturated steam;

Heat transfer coefficient:

$k=\frac{Q}{A{\mathrm{\Δt}}_m}---\left(2\right)$

Q＝m×γ _s （3）

In formula, m, γ _sbe respectively condensate quality that sleeve pipe collects and the latent heat of condensation of water, A is copper pipe external surface area to be detected, can be by copper pipe external diameter to be detected and length computation out.

Wherein, $k=\frac{1}{\frac{1}{h_i}\frac{d_o}{d_{\mathrm{in}}}+\frac{d_o}{2\mathrm{\λ}}\ln \frac{d_o}{d_{\mathrm{in}}}+\frac{1}{h_o}}---\left(4\right)$

In formula, h _ifor the copper pipe average surface coefficient of heat transfer (being the coefficient of heat transfer of copper pipe of the present invention), h _ofor managing the outer average condensation surface coefficient of heat transfer, the temperature conductivity that λ is copper pipe, d _ofor copper pipe overall diameter to be detected, d _infor copper pipe interior diameter to be detected.

Manage the rule of thumb formula employing of outer condensation heat transfer coefficient:

R, ρ _s, λ _s, μ _sbe respectively the latent heat of vaporization of steam under state of saturation, density, thermal conductivity and viscosity, t _wfor copper pipe hull-skin temperature to be detected.。

Repeating step (1) is to more than (4) three times and calculate copper pipe average heat transfer coefficient as the coefficient of heat transfer measured value of copper pipe.

Compared with prior art, the invention has the beneficial effects as follows: the vapor (steam) temperature while guaranteeing to enter double layer sleeve barrel from steam generator is all 100 ℃; Owing to having adopted the structure of double braid covering cartridge type, outer layer sleeve can be accomplished the complete thermal insulation to inner layer sleeve; Easy and simple to handle, and implement than being easier to.

Accompanying drawing explanation

Fig. 1 is the principle schematic of the mensuration system of a kind of copper tube heat exchange coefficient of the present invention.

Fig. 2 is the structural representation of bushing type test mechanism of the mensuration system of a kind of copper tube heat exchange coefficient of the present invention.

In figure, 1 is that water intaking valve, 2 exports, 21 is that inner sleeve exports for outer sleeve for heat-insulation layer, 20 for outer sleeve, 19 for outer sleeve import, 18 for inner sleeve, 17 for copper pipe, 16 for copper pipe outlet, 15 for copper pipe import, 13 for steam side valve, 12 for steam side thermometer, 11 for steam generator, 10 for pressure limiting valve, 9 for condensate collector, 8 for bushing type test mechanism, 7 for exit thermometer, 6 for differential manometer, 5 for inflow point's thermometer, 4 for flowmeter, 3.

Embodiment

Below in conjunction with figure and embodiment the present invention is described in further detail.

A mensuration system for copper tube heat exchange coefficient, as depicted in figs. 1 and 2, it comprises copper pipe import 12, copper pipe outlet 13 and bushing type test mechanism 6, described copper pipe import 12 and copper pipe outlet 13 are installed on respectively the both sides of described bushing type test mechanism 6.Described bushing type test mechanism 6 comprises inner sleeve 16 and outer sleeve 18, described inner sleeve 16 is installed in described outer sleeve 18, between described outer sleeve 18 and inner sleeve 16 sidewalls, form the overcoat cavity of sealing, described overcoat cavity is provided with outer sleeve import 17 and outer sleeve outlet 20; Described inner sleeve 26 is interior for installation test copper pipe 15, and between the sidewall of described test copper pipe 15 and the inwall of inner sleeve 26, forms the inner sleeve cavity of sealing, and described inner sleeve cavity is provided with inner sleeve import 14 and inner sleeve outlet 21.The outer sleeve import 17 of described overcoat cavity and outer sleeve outlet 21 are connected to form closed circuit with steam generator 9, for making inner sleeve 16 form stationary temperature.Described inner sleeve import 14 is connected with described steam generator 9, for being input into water vapor.In described copper pipe import, 12 places are provided with inflow point's thermometer 3 and flowmeter 2, and described copper pipe exports 13 places and is provided with exit thermometer 5.In described inner sleeve outlet 21, be connected with condensate collector 7, collect the condensate water flowing out from inner sleeve cavity.Described outer tube 18 lateral walls are enclosed with heat-insulation layer 19, further ensure the heat-insulating property of outer tube 18.In described copper pipe inflow point 12, be provided with water intaking valve 1.Between described copper pipe import 12 and copper pipe outlet 13, differential manometer 4 is installed, for detection of the pressure differential between two mouthfuls.On described steam generator 9, be provided with steam side thermometer 10 and pressure limiting valve 8, to guarantee safety, and be provided with steam side valve 11 between described steam generator 9 and inner sleeve import 14 and outer sleeve import 17.

Principle of work of the present invention is: the steam that steam generator 9 produces enters respectively described bushing type test mechanism 6, and the steam that steam generator 9 produces enters inside and outside sleeve from the inner sleeve import 14 of inner sleeve 16 and the import 17 of outer sleeve 18 respectively.Inner chamber steam heats experimental piece copper pipe outer wall, and the steam of overcoat cavity plays the effect to inner chamber thermal insulation.Outer sleeve is a simple cycle, and steam flows back to steam generator 9 from exporting 20 from outer sleeve import 17 enters.Steam condenses into water in inner layer sleeve, exports 21 condensations flow out from inner sleeve, and the water collector 7 that is condensed collects.Cold water flows into from the copper pipe import 12 of test copper pipe 15, then from the copper pipe outlet 13 of test copper pipe, flows out.

An assay method for copper tube heat exchange coefficient, on the basis of the mensuration system of above-mentioned copper tube heat exchange coefficient, its step comprises:

(1) by described bushing type test mechanism 6 dimensional requirements, prepare sample to be tested copper pipes, and sample copper pipe is arranged between the copper pipe import 12 and copper pipe outlet 1 in the inner sleeve 16 of described bushing type test mechanism 6.

(2) open water intaking valve 1, open steam generator 9, open steam side valve 10.

(3) control steam side thermometer and maintain 100 degree, wait for after a while, after temperature stabilization, record discharge, inflow point's temperature, exit temperature.

(4) steam off generator 9, steam side valve 10, water intaking valve 1 successively.

(5) according to following heat balance equation, utilize discharge, inlet temperature, outlet temperature, the copper pipe dimensional parameters measured, calculate the coefficient of heat transfer of copper pipe.

Heat balance equation is:

Mean temperature difference (MTD):

${\mathrm{\Δt}}_m=\frac{t_o-t_{\mathrm{in}}}{\ln \left(\frac{t_s-t_{\mathrm{in}}}{t_s-t_o}\right)}---\left(2\right)$

In formula, t _oit is the outlet temperature of water in pipe; t _inthe inlet temperature of water in pipe, t _sit is the temperature of saturated steam.

3) heat transfer coefficient:

$k=\frac{Q}{A{\mathrm{\Δt}}_m}---\left(3\right)$

Q＝m×γ _s （4）

(4) in formula, m, γ _sbe respectively the condensate quality of sleeve pipe collection and the latent heat of condensation of water.

Wherein, $k=\frac{1}{\frac{1}{h_i}\frac{d_o}{d_{\mathrm{in}}}+\frac{d_o}{2\mathrm{\λ}}\ln \frac{d_o}{d_{\mathrm{in}}}+\frac{1}{h_o}}---\left(5\right)$

In formula, h _ifor the copper pipe average surface coefficient of heat transfer (being the coefficient of heat transfer of copper pipe of the present invention), h _ofor managing the outer average condensation surface coefficient of heat transfer, the temperature conductivity that λ is copper pipe.

Manage the rule of thumb formula employing of outer condensation heat transfer coefficient:

R, ρ _s, λ _s, μ _sbe respectively the steam latent heat of vaporization under state of saturation, density, thermal conductivity and viscosity.

Repeating step (1) is to more than (5) three times and calculate copper pipe average heat transfer coefficient as the coefficient of heat transfer measured value of copper pipe.

An assay method for copper tube heat exchange coefficient, is used the mensuration system of above-mentioned copper tube heat exchange coefficient, and its step comprises:

(1) by the length of the mensuration system inner sleeve type test mechanism 6 of copper tube heat exchange coefficient, internal diameter and outside dimension requirement, prepare copper pipe to be detected, and copper pipe to be detected is arranged between the copper pipe import 12 and copper pipe outlet 13 of inner sleeve of bushing type test mechanism;

(2) open water intaking valve 1, open steam generator 9, open steam side valve 10;

(3) controlling steam side temperature is 100 degree, waits for a period of time, and records discharge, inflow point's temperature, exit temperature etc. after temperature stabilization;

(4) steam off generator 9, steam side valve 10, water intaking valve 1 successively;

(5) according to following heat balance equation, utilize discharge, inlet temperature, outlet temperature, the copper pipe size to be detected measured, calculate the coefficient of heat transfer of copper pipe:

Heat balance equation is:

Mean temperature difference (MTD) Δ t _m:

${\mathrm{\Δt}}_m=\frac{t_o-t_{\mathrm{in}}}{\ln \left(\frac{t_s-t_{\mathrm{in}}}{t_s-t_o}\right)}---\left(1\right)$

In formula, t _othe outlet temperature of water in pipe, t _inthe inlet temperature of water in pipe, t _sit is the temperature of saturated steam;

Heat transfer coefficient:

$k=\frac{Q}{\mathrm{A\Δ}{t}_m}---\left(2\right)$

Q＝m×γ _s （3）

In formula, m, γ _sbe respectively the condensate quality of sleeve pipe collection and the latent heat of condensation of water, A is copper pipe external surface area to be detected.

Wherein, $k=\frac{1}{\frac{1}{h_i}\frac{d_o}{d_{\mathrm{in}}}+\frac{d_o}{2\mathrm{\λ}}\ln \frac{d_o}{d_{\mathrm{in}}}+\frac{1}{h_o}}---\left(4\right)$

In formula, h _ifor the copper pipe average surface coefficient of heat transfer (being the coefficient of heat transfer of copper pipe of the present invention), h _ofor managing the outer average condensation surface coefficient of heat transfer, the temperature conductivity that λ is copper pipe, d _ofor copper pipe overall diameter to be detected, d _infor copper pipe interior diameter to be detected.

Manage the rule of thumb formula employing of outer condensation heat transfer coefficient:

Wherein, r, ρ _s, λ _s, μ _sbe respectively the latent heat of vaporization of steam under state of saturation, density, thermal conductivity and viscosity, t _wfor copper pipe hull-skin temperature to be detected.

Repeating step (1) is to more than (4) three times and calculate copper pipe average heat transfer coefficient as the coefficient of heat transfer measured value of copper pipe.

Claims (4)

1. the mensuration system of a copper tube heat exchange coefficient, it is characterized in that: comprise copper pipe import, copper pipe outlet and bushing type test mechanism, described copper pipe import and copper pipe outlet are installed on respectively the both sides of described bushing type test mechanism, described bushing type test mechanism comprises inner sleeve and outer sleeve, described inner sleeve is installed in described outer sleeve, between described outer sleeve and inner sleeve sidewall, form the overcoat cavity of sealing, described overcoat cavity is provided with outer sleeve import and outer sleeve outlet; Described inner sleeve is interior for copper pipe to be detected is installed, and between described copper pipe sidewall to be detected and inner sleeve, forms the inner sleeve cavity of sealing, and described inner sleeve cavity is provided with inner sleeve import and inner sleeve outlet; The outer sleeve import of described overcoat cavity and outer sleeve outlet are connected to form closed circuit with steam generator, and described inner sleeve import is connected with described steam generator; Described outer sleeve lateral wall is enclosed with heat-insulation layer; Described inner sleeve outlet is connected with condensate collector; Described copper pipe inflow point is provided with inflow point's thermometer and flowmeter, and described copper pipe exit is provided with exit thermometer; Between described copper pipe import and copper pipe outlet, differential manometer is installed.

2. according to the mensuration system of a kind of copper tube heat exchange coefficient claimed in claim 1, it is characterized in that: described copper pipe inflow point is provided with water intaking valve.

3. according to the mensuration system of a kind of copper tube heat exchange coefficient claimed in claim 1, it is characterized in that: on described steam generator, be provided with steam side thermometer and pressure limiting valve.

4. an assay method for copper tube heat exchange coefficient, is characterized in that: use the mensuration system of the copper tube heat exchange coefficient as described in as arbitrary in claim 1-3, its step comprises:

(1) by the length dimension requirement of the mensuration system inner sleeve type test mechanism of copper tube heat exchange coefficient, prepare copper pipe to be detected, and copper pipe to be detected is arranged between the copper pipe import and copper pipe outlet of inner sleeve of bushing type test mechanism;

(2) open water intaking valve, open steam generator, open steam side valve;

(3) controlling steam side temperature is 100 ℃, records discharge, inflow point's temperature, exit temperature after temperature stabilization;

(4) steam off generator, steam side valve, water intaking valve successively;

(5), according to following heat balance equation, calculate the coefficient of heat transfer of copper pipe:

Heat balance equation is:

Mean temperature difference (MTD) Δ t _m:

In formula, t _othe outlet temperature of water in pipe, t _inthe inlet temperature of water in pipe, t _sit is the temperature of saturated steam;

Heat transfer coefficient:

Q＝m×γ _s (3)

In formula, m, γ _sbe respectively the condensate quality of sleeve pipe collection and the latent heat of condensation of water, A is copper pipe external surface area to be detected;

Wherein,

In formula, h _ifor the copper pipe average surface coefficient of heat transfer; h _ofor managing the outer average condensation surface coefficient of heat transfer, the temperature conductivity that λ is copper pipe, d _ofor copper pipe overall diameter to be detected, d _infor copper pipe interior diameter to be detected;

Manage the rule of thumb formula employing of outer condensation heat transfer coefficient:

Wherein, r, ρ _s, λ _s, μ _sbe respectively the latent heat of vaporization of steam under state of saturation, density, thermal conductivity and viscosity, t _wfor copper pipe hull-skin temperature to be detected.