Although modern drying machinery drying technology has a history of more than one hundred years, it still belongs to the field of experimental science. Most drying technologies currently lack scientific theories and design methods that accurately guide practice. Therefore, before constructing industrial drying equipment, especially larger ones, it is necessary to conduct sufficient and convincing experiments, and use the experimental results as the basis for industrial equipment design. This is a distinctive feature of drying technology applications. In practical applications, relying on empirical and small-scale experimental data to guide industrial design is still the main way, the reasons for this situation are as follows: First, some basic disciplines relying on the drying technology of drying machinery and equipment (mainly subject to the discipline of transfer engineering) have the characteristics of experimental science. For example, the development of aerodynamic research is driven by the “wind tunnel†experiment, which indicates that it has not left the scope of experimental science, and the development level of these basic disciplines directly affects and determines the development level of drying technology. Second, the drying process of many dryers is a process of multi-disciplinary technology convergence, involving a wide range of factors, many changing factors, and complex mechanisms. For example, in the field of spray drying technology, the trajectory of the atomized droplets in the drying tower is the key to engineering design. The trajectory of the droplet is related to its volume, mass, initial velocity and direction, and the flow and velocity of other droplets and hot air around it. However, due to the mass transfer and heat transfer processes, these parameters change all the time, and in the initial state, neither the size of the droplets nor the distribution of hot air can be uniform. Obviously, engineering design based on theoretical calculations for such complex and varied processes is not reliable. Third, the types of materials to be dried are various, and their physical and chemical properties are also different. The mass transfer and heat transfer rates of different materials may be different even under the dry conditions of the same dryer. If not treated differently, it may have unsatisfactory consequences. For example, the drying of some Chinese herbal medicines, although belonging to the same medicinal materials, only needs to change the drying conditions because of the difference in the origin or harvest period of the medicinal materials, otherwise the quality of the products will be affected. The reasons for these three aspects determine that the development and application of drying machinery drying technology should be based on experiments. However, these characteristics of drying machinery drying technology are often ignored by people intentionally or unintentionally. Manufacturers often avoid the drying experiments that should be done because of the lack of experimental devices or incomplete models (which is a common phenomenon in China), and users often give up the necessary experiments because they do not understand the drying technology characteristics of drying machinery and equipment. Claim. The result is that the device is not working well and even causes the design failure.