【Q&A】April 28, 2017
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Question: What are the factors that affect heat transfer? Answer: A. Heat transfer area ； B. Heat transfer temperature difference ； C. Heat transfer coefficient K. http://bbs.hcbbs.com/static/image/hrline/4.gif Petrochemical Zone—New Ideas for Energy Saving: The “Creative Thinking” Campaign (Sponsors Wanted; Highest Returns Ever) http://bbs.hcbbs.com/thread-1666758-1-1.html Sponsors are being sought for this campaign; those interested can contact the event organizer. The Petrochemical Deep Processing Edition—sharing pictures of chemical equipment has started! A vast amount of wealth, as well as HaiChuan coins, are waiting for you to claim them: http://bbs.hcbbs.com/thread-1760733-1-1.html. “Petroleum and Chemicals Section”: Notice regarding the collection of chemical industry-related technical materials: http://bbs.hcbbs.com/thread-1614796-1-1.html. http://bbs.hcbbs.com/hcdown/data/attachment/forum/201704/07/123053embbjkok61hz6vvz.jpg.thumb.jpg. [HaiXin Chemical Cup ★ Spring has arrived for HaiChuan Chemicals] Summary post of the 2017 scenic views sharing event (you can take a look at the local scenery posted by users from various places in your free time): http://bbs.hcbbs.com/thread-1766484-1-1.html
Temperature, pressure, heat transfer area, thermal conductivity
The heat transfer coefficient of the medium, the heat exchange area, the temperature difference for heat exchange, or the heat grade
As can be seen from the heat transfer equation Q=K.F.△t, the amount of heat transferred is determined by three factors: the average temperature difference between the cold and hot fluids, the heat exchange area, and the heat transfer coefficient.
Factors that affect heat transfer include: 1. The types of fluids on both sides of the heat transfer process； 2. Flow rate in the heat transfer process ； 3. Is there a phase change in the heat transfer process? ； 4. Wall thickness of the flat wall ； 5. Thermal conductivity of flat walls, etc.
Factors affecting the convective heat transfer coefficient The convective heat transfer process is one in which heat is transferred between a fluid and a wall surface; therefore, any factor related to fluid flow and the wall surface will inevitably influence the value of the convective heat transfer coefficient. Experiments show that the value of the heat transfer coefficient is related to the causes of fluid flow. The flow pattern of the fluid is influenced by factors such as the fluid’s physical properties, whether there is a phase change in the fluid, as well as the geometry, size, and relative position of the heating surface. Generally, for fluids with similar properties, the heat transfer coefficient of forced convection is greater than that of natural convection. The convective heat transfer coefficient of turbulent flow is greater than that of laminar flow; for the same type of flow, the higher the flow velocity, the greater the convective heat transfer coefficient. The physical properties of a fluid include its viscosity, thermal conductivity, density, specific heat capacity, and coefficient of volume expansion, among others. For heat transfer with phase change, the effect of the latent heat of phase change also plays a role; aside from viscosity, as other physical properties increase, the convective heat transfer coefficient increases accordingly. For the same fluid, the heat transfer coefficient with phase change is greater than that without phase change. The shape, size, and relative position of heat transfer elements affect the heat transfer process. For example, when heating a room in winter, the heating surfaces should be placed at the lower part of the space; conversely, in summer, cooling devices should be placed at the upper part of the space.
Temperature difference between the two media, size of the contact surface, duration of contact
As can be seen from the heat transfer equation Q=K.F.△t, the amount of heat transferred is determined by three factors: the average temperature difference between the cold and hot fluids, the heat exchange area, and the heat transfer coefficient.
Temperature difference, material properties, heat exchange area, heat exchange tube material, etc
As can be seen from the heat transfer equation Q=K.F.△t, the amount of heat transferred is determined by three factors: the average temperature difference between the cold and hot fluids, the heat exchange area, and the heat transfer coefficient.