Analysis Of Heat Transfer And Mathematical Physics Modelling In Moxibustion With Moxa-stick

The moxibustion or moxa treatment is a rich experience of ancient Chinese laboring people drawing from long period' s battles against the disease. It is an important part of national medicine. And it is a kind of external treatment worth studying, applying and disseminating, which can prevent and cure disease and make people stronger and healthier. The curative effect is a prerequisite to the application and dissemination of treatment. And the effect appears through proper amount of application. The moxibustion has exact curative effect fully proved by many doctors' studies. But there is no certain amount of moxibustion application in line with the effect. Most researchers nowadays apply biological methodology to explore the best function parameters of moxibustion application. Their research results are limited to some extent. In many researches on moxibustion mechanism, heat function is one of the generally accepted and important function mechanisms, and it is not thoroughly studied yet. Biological heat transfer is such a subject used to study the law of heat and material transfer in tissues by incorporating theory and heat transfer methodology into biological and medical engineering. The generation of this subject will give inspiration to the study of moxibustion closely related with heat. We started with the energy, selected physical knowledge, adopted the theory of bio-heat transfer, combined experiment means and researched the law of temperature distribution (energy process) in tissues by moxibustion with moxa-stick. Then we also tried to find out the relationship of that law with different amount of moxibustion with moxa-stick applications and the condition of health and disease. By this way, we want to provide some data support to curative effect and controllable application of moxibustion. Firstly, we reviewed the study situation and meaning of moxibustion function from ancient to modern times. Then we put forward the rationality and target of bio-heat transfer theory in moxibustion study. We thought the study did not yet break through the traditional theoretical restraint, because of many unclear physical and chemical parameters in moxibustion and little data based on modern science. On the basis of past researches, we discussed the heat function of moxibustion, and thought there was some relationship between moxibustion and tissues by heat in micro and macro structure. The heat of moxibustion can lead to temperature rise in tissues, but the heat transfer is just caused by energy transfer in essence. So we mainly discussed the key function due to curative effect made by the just heat transfer process (energy transfer process). Temperature is used to describe the distribution of energy. We pointed out the importance that knowing the law of temperature dynamic field. We thought the dynamic temperature variations did lead to different organ reaction, in this way we might judge the curative effect.Secondly, on the basis of energy conservation law, bio-heat transfer equation involved was explained. Basic theory of heat transfer was shown. The main content of bio-heat transfer theory was indicated. Although bio-tissues are so complex and diversified, the heat transfer in tissues and between tissues and surrounds still belongs to three elementary styles and their combined one, that is heat conduction in solid tissues, convection heat transfer in blood and body fluid, radiation heat transfer between tissues and surrounds, and the material transmitting in heat transfer process. All obey the laws of thermodynamics. The tissues are heterogeneity and anisotropy. But the macroscopic conductivity is concerned, or the tissues temperature variety is wanted. According to the laws of thermodynamics and heat transfer, bio-heat transfer equation can be established and used to calculate the tissues temperature distributions. The widely used PENNES model was shown. Solution conditions of the equation were summarized entirely. Tissue thermal properties were expressed and some formulas and data were shown. The thermal properties of kidney-yang deficiency tissues were estimated. The meaning of inverse heat conduction problem and temperature controlling were discussed. Methods of temperature measurement were shown and we chose thermocouple in our experiment. Heat injury model was expressed and it makes it clear that temperature gives more influence in injury than time. Thirdly, according to heat radiation theory, mathematical and physical model of energy transfer in moxibustion with stick was deduced. For spectrum characteristic of burning moxa, we treated the stick as spot radiation. And the equation was shown based on Planck' s law, Stefan-Boltzmann' s law, Lambert' s cosine law and G Kirchhoff' s law. Basic burning characteristics of moxa were analyzed. We thought that the moxa-stick' s burning is a kind of smoldering. Three main areas were described, such as ash area, carbon combustion area and pyrolysis area. Temperature of burning moxa-stick was measured by contact type (mini thermocouple) and not-contact type ( infrared radiation thermometer), which was included made moxa-stick. We used thermocouple, temperature conversion module and computer to collect and put out temperature curve of burning moxa-stick. Maximum temperature, temperature variation rate, high temperature duration and smoldering rate were calculated. Temperature in different areas of moxa-stick was recorded by infrared radiation thermometer. Moxibustion' s temperature range was defined according to the experiment result and clinical operation. Periodic burning temperature of moxa-stick was expressed by formula. And the variety temperature curve used in experiment was imitated by software.Fourthly, the bio-heat transfer equation was solved numerically. Solution of nonlinear partial differential equation was explained. The compute area was divided to two dimensions in the axial symmetry cylinder coordinate. The finite element method realized by MATLAB software is used to solve the equation. Tissue temperature distribution was calculated and can display in two or even three dimensions dynamically. Temperature response of several moxibustion with moxa-stick applications was simulated, such as model of healthy living rat (SD) skin, model of kidney yang-deficiency living rat (SD) skin, model of isolated porcine skin, model of living human skin. Temperature of space distribution and time behavior on different conditions by moxibustion with moxa-stick can be shown clearly from the simulation results. The influence of moxibustion time, moxa-to-skin distance, blood perfusion and multi-layers to calculation results was analyzed. That included: distance is more active than time in moxibustion with same moxa-stick to change the tissue's temperature; multi-layers tissue is more sensitive than single-layer one to the change of thermal flux by moxibustion; tissues of kidney yang-deficiency earlier store heat energy than the one of healthy; vivo tissues manifest higher conduction rate than vitro ones; etc. Then solve of temperature was exported to estimate the heat injury degree by the model. So some clinical guides were provided.Finally, in order to validate the veracity of theory model and calculation, an experiment system used in minimally invasive temperature measuring by moxibustion with moxa-stick was constructed. This system used mini needle thermocouple to monitor the inner and surface temperature synchronously. Such a system is suitable to high precision, minute point and rapid response temperature measuring. The process and result were recorded about making model of kidney-yang deficiency rats by injecting hydrocortisone. Several group of experiments by changing the amount applications of moxibustion with moxa-stick (size and quantity of moxa-stick, moxa-skin distance, moxibustion time) were carried out after tissue samples were prepared. Temperatures in several tissues (isolated porcine tissue, healthy living rat skin, kidney-yang deficiency living rat skin) were measured on line. The law of temperature distribution in physiological and pathological tissues by moxibustion with moxa-stick was recorded and contrasted. Meridians and collaterals function in moxibustion was observed. Main influence factors were summed and analyzed.The result proved the prediction and experiments about tissue surface have well coherence. A few point temperatures can be got in experiment, while complete information of dynamic temperature distributions can be got through numerical simulation. That shows the superiority of mathematics physics model in estimating temperature in tissues by moxibustion with moxa-stick. Moxibustion with moxa-stick is a kind of course to shock organism with energy. How to get well curative effect with appropriate moxa-stick size, right moxibution time and moxa-skin distance, and just period function? Some data from model calculating and experiments were given. However, for the complexity of moxa burning, the difference of tissues and the individuality of organism, the result was not perfect. Further study on precise description should be performed. The method of numerical simulation involved is to give well play in study on quantification of relationships between application amount and curative effect by moxibustion with moxa-stick.