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Studies on isobaric specific heat capacity of liquid under high pressure

高压液体等压比热容的研究

基本信息

批准号：
02650690
负责人：
KUBOTA Hironobu
金额：
$ 1.54万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

Thermophysical properties of fluids, such as heat capacity and enthalpy, are important for various process calculations. Although, these properties can be calculated by the experimental PVT data or the equation of state, it is very difficult to estimate reliably the errors in the first and second derivatives of these PVT properties. Therefore, the direct experimental determination of heat capacity is desirable.A new adiabatic flow calorimeter was designed and constructed. In this calorimeter, steady flow of liquid past a thermometer, a heater and second thermometer under a constant pressure. By measurement of the flow rate, of power input to the heater and of liquid temperatures at inlet and outlet of the calorimeter, the apparent heat capacity of the sample liquid may be calculated. Usually there are some heat losses, therefore an adequate correction should be made to obtain the true heat capacity. This calorimeter can measure the isobaric heat capacity, Cp, of pure liquids and their mixtures precisely and conveniently in the temperature range from 230 to 420K and pressures up to 4OMPa. The uncertainty of the measurements is estimated to be within <plus-minus>2.1At first, the isobaric specific heat capacity of HCFC123 (CH_3CHCl_2) whose heat capacity data were reported in the literature was measured to confirm a reliability of this apparatus and procedure. Measurements were carried out at the temperature 310.2 and 320.2K and pressure 1.0MPa. The present results agree with the literature values within the experimental uncertainty. The heat capacity of HCFC14lb (CH_3CCl_2F) was measured at temperature from 303 to 323K and pressures up to 1.0MPa. In this experimental conditions, heat capacities obtained decreased monotonously with increasing pressure.

流体的热物理性质，如热容和热焓，对各种工艺计算都很重要。虽然这些性质可以通过实验PVT数据或状态方程来计算，但要可靠地估计这些PVT性质的一阶和二阶导数的误差是非常困难的。因此，热容的直接实验测定是可取的。设计并建造了一种新型绝热流动量热计。在这个量热计中，液体在恒定压力下稳定地流经温度计、加热器和第二温度计。通过测量流量、输入加热器的功率以及量热计进出口的液体温度，可以计算出样品液体的表观热容。通常会有一些热损失，因此应进行适当的修正，以获得真实的热容量。该量热计可在230~420K的温度范围内，在40 Mpa的压力下，准确、方便地测量纯液体及其混合物的恒压热容Cp。测量的不确定度估计在&lt；正负&gt；2.1。首先，测量了文献报道的热容数据的HCFC123(CH_3CHCl_2)的恒压比热容，以证实该装置和方法的可靠性。测量温度为310.2℃，温度为320.2K，压力为1.0 MPa。在实验不确定度范围内，所得结果与文献值相符。在303~323K温度和1.0 MPa压力下，测定了HCFC141b(CH3CCl2F)的热容。在本实验条件下，测得的热容随压力的增加而单调下降。