The analysis of the factors that influence the heat transfer of water

Abstract

A hot bath is becoming a necessary event of people’s life. The temperature field of water in a bathtub is coomplex and always influenced by a series of factors, such as human body, bubble bath agent,the shape of the container. Introduction consider the motion of the human body, the process in water cannot considered as a normal heat conduction, the process human body absorbs part of the heat is equivalent to add a minus density of heat flow rate and build new convective heat transfer simultaneous differential equations. The bubbles’ affect to a temperature field is equivalent to add an insulating layer over the surface of the water. Analysis The materials of common bathtub are Acrylic and glass fiber, etc. The thermal conductivity of the acrylic is 1.4 W/m*K, the thermal conductivity of glass fiber is 1.09W/m*K, the smaller thermal conductivity thermal insulation effect is better. The wall of the bathtub is simplified as an adiabatic wall. A water temperature change model of bathtub is established from the view of time and space, in order to ensure not to waste too much water, select periodic watering measures, In the case of known room temperature, the initial temperature of the bath water, the shape of the bathtub and the initial water height. Put forward the strategy of reducing excessive waste water by adjusting the hot water temperature and hot water flow also with intermittent supply of hot water. The bathtub filled with water and people in the water, when the water is stable, people on the water surface and the water reaches temperature equilibrium is zero. When people in the water and the body surface and water reach the temperature relative balance is zero moment. 1liquid stable fixed, natural convective heat transfer on the water surface temperatures decreasing three-dimensional non-steady heat conduction process; 2Process of adding hot water, the temperature gradually increased until close to the initial temperature.According to the heat conduction process of the water, a three-dimensional unsteady heat conduction model is established in process1. According to the given boundary conditions, the temperature of any point in the water can be calculated at any moment; in process hot water through the faucet to join the water temperature in the heating bath, the ratio of the opening area of the bathtub and the outlet area of the faucet is expressed by 1000 ' s s  , The volume flow of the overflow water from the opening of the bathtub is the same as that of the tap, so the ratio of the speed of the water to the faucet is less than 1000. Ignore the rate of rise, taking into account this time; add hot water and surface heating on the human body, will continue to add hot water added as a two-part process: Ignore the rising speed of water, taking into account this time, the hot water will be added to the body surface heating, The process of adding hot water Continuously will be regarded as addition of two parts: one part is joining a continuous heat flow for a period of time, another part is adding the same amount of water as the same as the initial water temperature. Heat flux into the heat flow, including water absorption and people heat absorption. A complex dynamic process is decomposed into two single dynamic processes and a single static process, the corresponding model is 5th International Conference on Advanced Materials and Computer Science (ICAMCS 2016) © 2016. The authors Published by Atlantis Press 776