-
加热器
简介
Introduction to Heaters
电加热器
广泛用于各种需要提高对象或过
程温
度的场合。
例如，
润滑油在注入机器前
需要进行加温，
管道可能需要伴热以防止在
较冷环境中冻结。<
/p>
电加热器可将电能转化为
热能，
然后通过
不同的热传递方式将热能传
递给过程。
Electric heaters are used in a variety
of processes
where the temperature of
an object or process
needs to be
increased. For example, lubricating oil
need to be warmed before it is fed to a
machine, or
,
a pipe might
need heat tracing to prevent it from freezing in
the cold. Electric heaters work by
converting electrical energy into heat.
The heat is then transferred to the process
through
various forms of heat
transfer
.
热传递方式
Methods of Heat
Transfer
对流：
对流式热传
递是指通过流体（例如液体或气体）的运动来传递热量。对
流分为两种主要的形式，即自
由对流和强制对流。自由对流是指流体在热梯度
影响下自然流动。例如，热空气上升，冷
空气下沉，热空气不断向冷空气上方
移动的趋势即形成自然对流。随着空气的运动，热空
气中的部分热量将传递给
相对较冷的空气。
< br>强制对流是指通过施加外力来加速流体的流动。例如，通过风扇或搅拌器促使
气体
或液体发生运动，形成强制对流。
Convective:
Convective heat
transfer occurs when heat is transferred due to
the motion of a
fluid (such as a liquid
or gas). There are two primary forms of
convection, free convection and
forced
convection. Free convection occurs when the fluid
naturally flows due to heat gradients.
For example, hot air rises, and cold
air sinks, so natural convection describes the
tendency for
hot air to move above cold
air
. As the air is in motion, some of
the heat from the hot air is
transferred to the cooler
air
.
Forced
convection describes situations where an external
force is used to accelerate the flow of
a fluid. Using a fan or stirrer to
create movement in a liquid or gas would be an
example of
forced
convection.
传导：
传导
性热传递是固体最为常见的热传递方法。热量传递给固体后，构成
固体的原子（或粒子）
开始逐渐升温并加速振动。振动所产生的能量再传递给
临近的原子，使临近原子也开始变
热。传导性加热通常用于固体，因为固体具
有致密且重复的分子结构。
< br>
Conductive:
Conductive
heat transfer is the most common method of heat
transfer for solids.
As heat is
transferred to a solid, the microscopic atoms (or
particles) that form the solid, begin
to get hotter and vibrate more rapidly.
The energy from the vibrations is transferred to
neighboring atoms, which begin to get
hotter as well. Conductive heating is typically
used on
solids since they have a dense,
repeating molecular structure.
辐射：
辐射热传递是通过电磁波传递
热量的过程。温度高于绝对零度的物体会
在粒子随机运动的作用下发射热能。这些热能以
电磁波的形式从物体中发出。
之后，电磁波中的能量可加热周围的固体、液体和气体。辐
射热能的常见示例
包括我们从太阳光中感受到的热能和传统烤箱中用于烹调食品的热能。
Radiant:
Radiant
heat transfer is the transfer of heat using
electromagnetic waves. Objects at
a
temperature above absolute zero emit thermal
energy due to the random movement of their
particles. The thermal energy is
emitted in the form of electromagnetic waves,
which propagate
from the object. The
energy in these waves can then heat surrounding
objects, fluids, and
gases. Common
examples of radiant heat include the heat we feel
from the Sun and the heat
used to cook
objects in a traditional oven.
选择加热器时的重要考量因素
在选择
要使用的加热器前，
应考虑应用的具体特点，
主要是所加热介质
的类型，
以及所需热能的多少。
有些加热器专用于加热油性、<
/p>
粘性或腐蚀性溶液。
然而，
并非所有加热
器都可以用来加热任何物质。
确认所需加热器不会被相应过程损
坏是非常必要的。
mportant
Considerations when Choosing a Heater
It is important to consider the
specifics of your application prior to selecting
the heater to use.
Of primary concern
is the type of medium being heated and the amount
of heating power
required. Some heaters
have been specially designed to function in oils,
viscous, or corrosive
solutions.
However
, not all heaters can be used
with any material. It is important to confirm the
desired heater will not be damaged by
the process.
此外，
还
应确保所选电加热器的规格适当。
应确定并验证加热器的电压和功率。
< br>功率密度也是一项重要的考量指标。
功率密度是指每平方英寸加热表面的热流
量。此参数表示热量传递的密集程度。
In addition, it is necessary to select
an electric heater that is appropriately sized. Be
sure to
determine and verify the
voltage and wattage for the heater
. One
important metric to consider
is Watt
Density. Watt density refers to the heat flow rate
per square inch of surface heating. This
metric shows how densely the heat is
being transferred.
加热器
类型
Types of
Heaters