Device and method for measuring specific heat capacity and phase change latent heat of substance

A technology of phase change latent heat and specific heat capacity, applied in the field of thermophysical property measurement of substances, can solve the problems of calorimetric liquid temperature drop, easy volatilization, measurement error, etc., and achieve the effect of small equipment size and simple operation

Active Publication Date: 2019-03-29
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the existing mixing method specific heat capacity testing technology, water is used as the calorimetric liquid. This is mainly because the cost of water is low and the thermal physical property data is easy to obtain. However, water is not the most ideal calorimetric liquid. First, water is heated It is easy to volatilize, and absorbs a large amount of heat when evaporating, causing the temperature of the calorimetric liquid to drop, and resulting in a decrease in the mass of the calorimetric liquid, resulting in an error in the measurement result. When the measurement temperature is higher, the error will be greater; secondly The specific heat of water is twice or even 10 times that of ordinary liquids and solids. Therefore, in the measurement, it is necessary to require a large temperature difference between the initial heating temperature of the object to be measured and the temperature of the water, otherwise the temperature of the water will change very little during the measurement. Due to the accuracy of temperature difference measurement, there will be a large error in the specific heat measurement result of the measured object

Method used

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  • Device and method for measuring specific heat capacity and phase change latent heat of substance
  • Device and method for measuring specific heat capacity and phase change latent heat of substance
  • Device and method for measuring specific heat capacity and phase change latent heat of substance

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0078] Embodiment 1: to the specific heat capacity measurement of solid red copper

[0079] Take a copper block of a certain volume, punch a small hole in the copper block for suspension, then weigh its mass as 0.15687kg, stick the thermistor on the surface of the copper block, and hang it in the constant temperature aluminum block with a thin fishing line For temperature control, pour a certain mass of ethylene glycol into the calorimeter and keep it at a constant temperature, and use a thermistor to measure the temperature of ethylene glycol. When the temperature of the copper block and ethylene glycol no longer changes, quickly put the copper block into the ethylene glycol, when the temperature of the two thermistors no longer changes, record the equilibrium temperature at this time, according to Calibrate the heat capacity of the calorimeter obtained, and measure the specific heat capacity of the measured object. After completing an experiment, clean the copper block, rew...

Embodiment 2

[0082] Embodiment 2: to the specific heat capacity measurement of 304 stainless steel powder

[0083] Take a certain quality of 304 stainless steel powder, wrap it with a 500-mesh nylon net, embed the Pt-100 platinum resistance chip in the 304 stainless steel powder, draw it out with three 0.1mm enamelled copper wires, and hang the nylon net with a thin fishing line The temperature is controlled in a constant temperature aluminum block, a certain mass of ethylene glycol is poured into the calorimeter and kept at a constant temperature, and the temperature of the ethylene glycol is measured using a Pt-100 platinum resistance chip. When the temperature of the copper block and ethylene glycol no longer changes, quickly put the nylon mesh and 304 stainless steel powder into the ethylene glycol, when the temperature of the two Pt-100 platinum resistance chips no longer changes, record At this equilibrium temperature, the specific heat capacity of the measured object is measured acc...

Embodiment 3

[0087] Embodiment 3: the measurement of paraffin wax specific heat capacity and phase change latent heat

[0088] It is known that the starting melting temperature of a certain paraffin is 41.1°C, and the complete melting temperature is 43.9°C. Weigh different qualities of paraffin and ethylene glycol respectively, put the paraffin in an ultra-thin plastic bag, place it in a constant temperature aluminum block to control the temperature to different temperatures, and wait for the temperature of the tested sample to be constant, put it quickly After entering the ethylene glycol at constant temperature for heat exchange, after the temperature of paraffin wax and ethylene glycol no longer changes, the equilibrium temperature is measured, and the specific experimental data are shown in Table 4.

[0089] Three groups of results that table 4 embodiment 3 measures

[0090]

[0091] Using the fitting software 1stOpt to fit, the solid specific heat capacity of paraffin wax is 2663....

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Abstract

The invention provides a device and method for measuring the specific heat capacity and phase change latent heat of a substance. The device comprises a calorimeter component and a sample temperature control component. The calorimeter component comprises a calorimeter. A magnetic stirrer used for stirring a calorimetric liquid in the calorimeter is arranged at the bottom of the calorimeter. A temperature difference thermocouple and a first temperature sensor are arranged in the calorimeter. The sample temperature control component is located above the calorimeter. The sample temperature controlcomponent comprises a thermostatic aluminum block. A platinum resistance thermometer and a tested sample are arranged in the thermostatic aluminum block. A second temperature sensor is arranged on the tested sample. The calorimetric liquid is ethylene glycol. The calorimeter is in a double-layered sleeve structure. According to the invention, the device can accurately measure the specific heat capacity of a solid and liquid and the phase change latent heat of a solid-liquid phase change material; the stability of the device is great; a wide temperature range can be measured; and the device can be used for measuring the specific heat capacity and phase change latent heat of materials in industry and scientific research, and can be used for teaching experiments of energy and power related professional courses.

Description

technical field [0001] The invention relates to the measurement of thermophysical properties of substances, in particular to a device and method for measuring the specific heat capacity of substances and latent heat of phase change, which can be used in the teaching of energy, power and thermodynamics-related professional course experiments, and can also be used in industry and scientific research Measurements of specific heat capacity and latent heat of phase change in related substances. Background technique [0002] Specific heat capacity is a commonly used physical quantity in thermodynamics, which indicates the ability of an object to absorb heat or dissipate heat. Different substances have different specific heat capacities. Specific heat capacity is a characteristic of substances. Substances at different temperatures have different specific heat capacities. As an important property of matter and data of theoretical analysis, specific heat capacity is widely used in ac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N25/20
CPCG01N25/20
Inventor 张可闫少敏余东东王康毕胜山吴江涛
Owner XI AN JIAOTONG UNIV
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