【正文】 ，導熱系數(shù)K。粒子可能是液體，固體或液體包圍了堅實的核心。這一政策已重新在水和冰蓄冷的興趣。風冷冷凝器越過室外空氣凝結(jié)的制冷劑的干燥線圈。通常是由大氣冷卻水從冷凝器。風冷冷凝器越過室外空氣凝結(jié)的制冷劑的干燥線圈。確定搬遷戰(zhàn)略和設備時，粒子和氣體之間的區(qū)別是重要的的。比例系數(shù)，導熱系數(shù)K。如果是內(nèi)部所產(chǎn)生的溫度變化所造成的非均質(zhì)密度的流體流動，傳熱稱為自然對流或自然對流。 most fluids in the HVAC industry (., water, air, most refrigerants) can be treated as Newtonian. In nonNewtonian fluids, the relationship between the rate of deformation and shear stress is more plicated.粘度是流體的抗剪切的措施。The second law of thermodynamics differentiates and quantifies processes that only proceed in a certain direction (irreversible) from those that are reversible. The second law may be described in several ways. One method uses the concept of entropy flow in an open system and the irreversibility associated with the process. The concept of irreversibility provides added insight into the operation of cycles. 熱力學第二定律的區(qū)別和量化，只有在某一個方向，是可逆的（不可逆）進行的過程。A cycle is a process or a series of processes wherein the initial and final states of the system are identical. Therefore, at the conclusion of a cycle, all the properties have the same value they had at the beginning. A pure substance has a homogeneous and invariable chemical position. It can exist in more than one phase, but the chemical position is the same in all phases一個周期進程的一個過程或一個系列，其中系統(tǒng)的初始和最終狀態(tài)是相同的的。焓H，一個屬性相結(jié)合的結(jié)果，被定義為：H = U + PV其中u是每單位質(zhì)量的內(nèi)部能量Each property in a given state has only one definite value, and any property always has the same value for a given state, regardless of how the substance arrived at that state. A process is a change in state that can be defined as any change in the properties of a system. A process is described by specifying the initial and final equilibrium states, the path (if identifiable), and the interactions that take place across system boundaries during the process. 中的每一個給定的狀態(tài)的屬性只有一個定值，和任何財產(chǎn)總是有相同的值給定的狀態(tài)，不管如何抵達該國的物質(zhì)。最常見的熱力學性質(zhì)的溫度T，壓力P，和特定的體積V或密度ρ。這些邊界可以是動產(chǎn)或固定的，真實的或想象?？赡嫜h(huán)有兩個重要的屬性：（1）無制冷循環(huán)的性能系數(shù)之間相同的溫度限制經(jīng)營的可逆循環(huán)高于，（2）之間相同的溫度極限運行時，所有可逆循環(huán)，同樣的性能系數(shù)Flowing fluids in heating, ventilating, airconditioning, and refrigeration systems can transfer heat, mass, and momentum. This chapter introduces the basics of fluid mechanics related to HVAC processes, reviews pertinent flow processes, and presents a general discussion of singlephase fluid flow analysis.流動的液體在加熱，通風，空調(diào)和制冷系統(tǒng)，可以傳遞熱量，質(zhì)量和動量。Heat is energy in transit due to a temperature difference. The thermal energy is transferred from one region to another by three modes of heat transfer: conduction, convection, and radiation. Heat transfer is among a group of energy transport phenomena that includes mass transfer, momentum transfer or fluid friction and electrical conduction. 熱是由于溫差在傳輸過程中的能量。減號表示熱流溫度降低的方向積極。他們中的濃度每立方厘米在受污染的城市環(huán)境的范圍在清潔的環(huán)境中從100 particles/cm3百萬的氣氛。存儲容量為夏季負荷平衡安裝，也可能是在冬季使用，高熱不退更可行的選擇。無論是自然通風或機械通風冷卻塔或噴池塘用于拒絕到大氣中的熱量。Air contaminants are generally either particles or gases. The distinction between particles and gases is important when determining removal strategies and equipment. Although the motion of particles is described using the same equations used to describe gas movement, even the smallest of particles (approximately 1 nm) are much larger than individual gas molecules, have a much greater mass, and a much lower diffusion rate. 空氣污染物一般是顆粒或氣體。公式（1）在x方向的熱流率q是成正比的溫度梯度DT/ DX和橫截面積一個正常的熱流。When fluid currents are produced by external sources (for example, a blower or pump), the solidtofluid heat transfer is termed forced convection. If the fluid flow is generated internally by nonhomogeneous densities caused by temperature variation, the heat transfer is termed natural convection or free convection.When fluid currents are produced by external sources (for example, a blower or pump), the solidtofluid heat transfer is termed forced convection. If the fluid flow is generated internally by nonhomogeneous